Basal Plane Orientation Research Articles

(Invited) Atomic Layer Processing of MoS2

Molybdenum disulfide (MoS2) is one of several transition metal dichalcogenides consisting of a layer of transition atoms sandwiched between layers of chalcogens. Interest in MoS2 has been driven by its 1.8 eV direct electronic band gap in monolayer form and its moderate electron mobility (10-100 cm2/Vs) even when only three atoms (~6.5 Å) thick. These properties offer potential for retaining or improving speed and efficiency in scaled electronic devices.Advancing MoS2 and other 2D materials into high volume manufacturing of semiconductor devices requires scalable deposition and etching processes. The process of atomic layer deposition (ALD) has been used to deposit 2D materials and can deposit films at lower temperatures for back-end-of-line (BEOL) compatibility. However, ALD relies on covalent surface reactions. When these reactions occur at high density during film nucleation, the resulting film is typically amorphous or nanocrystalline and requires thermal annealing to form a more well-ordered layered crystal structure. A key challenge is to establish a low temperature ALD process that achieves a layered crystal structure with low defectivity. In terms of material removal, MoS2 films have been etched by plasma-based atomic layer etching (ALE). ALE is analogous to ALD except that cyclic surface reactions promote volatility and lead to film removal rather than deposition. Together, atomic layer deposition and atomic layer etching constitute complementary facets of atomic layer processing and enable new pathways for nanomanufacturing.Here, we describe our recent progress in thermal ALD and thermal ALE of MoS2 films. For ALD of MoS2, we use cycles of MoF6 and H2S between 150-350 °C. Nucleation on metal oxide surfaces shows a strong temperature dependence, which is attributed in part due to the temperature dependence of surface hydroxyl groups. Density functional theory (DFT) calculations support the role of hydroxyls in promoting nucleation and reveal that MoF6 dissociates on the surface rather than participating in a ligand exchange reaction. The dissociation reaction leads to the formation of a metal fluoride interface between the oxide surface and the MoS2 film. Surface species following MoF6 include MoOF4 and MoO3, both of which convert to MoS2 during the H2S pulse, which releases H2O and HF byproducts. Films deposited at 200 °C and below are amorphous but convert to a layered structure upon annealing in H2S. Deposition at 250 °C yields films with a layered crystal structure without post-deposition annealing.Thermal ALE of MoS2 films deposited by ALD can be achieved using alternating exposures of MoF6 and H2O. It was found that MoS2 films are fluorinated by the MoF6 and then oxygenated by H2O. Volatile byproducts are MoF2O2, H2S, and HF, which are primarily released during the H2O half-cycle. Thermal ALE of MoS2 is temperature dependent and follows Arrhenius behavior. At 200 °C, the mass loss per cycle is 6 ng/cm2 (~0.5 Å/cycle) and reaches 271 ng/cm2 at 300 °C. Etch stop behavior was observed once the etched film approached the metal fluoride interface of the growth surface. Layered MoS2 deposited by ALD with post-deposition annealing exhibited layer-by-layer etching at 0.2 Å/cycle at 250 °C.The ALD results provide key insights into the nucleation and growth of MoS2 films using low temperature ALD. Further work is required to control basal plane orientation but achieving crystalline films well within BEOL thermal budgets is promising. The results from the ALE study provide insights into the etching reactions for MoS2. Combining the two processes offers greater control over MoS2 films. Using ALD followed by ALE and post-deposition annealing, we achieved few-layer MoS2 films. These combined thermal processes represent a pathway for integration of MoS2 films into device manufacturing.

Scrutinizing pre- and post-device fabrication properties of atomic layer deposition WS2 thin films

In this work, we investigate the physical and electrical properties of WS2 thin films grown by a plasma-enhanced atomic layer deposition process, both before and after device fabrication. The WS2 films were deposited on thermally oxidized silicon substrates using the W(NMe2)2(NtBu)2 precursor and a H2S plasma at 450 °C. The WS2 films were approximately 8 nm thick, measured from high-resolution cross-sectional transmission electron imaging, and generally exhibited the desired horizontal basal-plane orientation of the WS2 layers to the SiO2 surface. Hall analysis revealed a p-type behavior with a carrier concentration of 1.31 × 1017 cm−3. Temperature-dependent electrical analysis of circular transfer length method test structures, with Ni/Au contacts, yielded the activation energy (Ea) of both the specific contact resistivity and the WS2 resistivity as 100 and 91 meV, respectively. The similarity of these two values indicates that the characteristics of both are dominated by the temperature dependence of the WS2 hole concentration. Change in the material, such as in sheet resistance, due to device fabrication is attributed to the chemicals and thermal treatments associated with resist spinning and baking, ambient and UV exposure, metal deposition, and metal lift off for contact pad formation.

Study on localized corrosion behavior of hot extrusion deformed GW103K magnesium alloy

This study investigated the corrosion behavior in the core and at the edge of the cross-section of an extruded GW103K (Mg–10Gd–3Y–0.4Zr) alloy. Equivalent stress and strain were modeled using finite element simulations. The stress and strain in the core were lower than those at the edge. The microstructure, corrosion morphology, and grain orientation of the alloy were examined using optical microscopy, scanning electron microscopy, and electron backscatter diffraction, respectively. The results showed that most grains in the core exhibited a basal plane orientation and lower surface energy, whereas those at the edge exhibited cylindrical orientations. Hydrogen evolution experiments and electrochemical tests showed that the corrosion resistance in the core was higher than that at the edge. Scanning Kelvin probe force microscopy measurements of the surface potential distribution in the cross-section revealed a large potential difference between the second-phase particles at the edge and the matrix, with obvious galvanic corrosion. The alloy core exhibited low stress and a higher content of grains with basal plane orientation, along with a small potential difference between the second-phase particles and the matrix. Thus, the corrosion resistance in the core was higher than that at the edge.

On rate dependence and anisotropy in phase field modeling of polycrystalline fracture

A phase field theory of fracture incorporating rate dependence (i.e., kinetic viscosity) and anisotropic elasticity is implemented to study strength and failure modes in polycrystalline materials. After presentation of the constitutive framework, a new analytical solution is derived for one-dimensional (1D) homogeneous loading at constant strain rate, wherein crack viscosity is enabled. The three-dimensional (3D) theory is implemented in a finite element (FE) context, with static and dynamic solutions verified up to peak loading for homogeneous microstructures. Extensive simulations of heterogeneous polycrystalline microstructures follow, where baseline material properties correspond to either boron carbide (B4C) or titanium diboride (TiB2). Results quantify effects of loading rate, elastic anisotropy, cleavage energy anisotropy, and grain boundary surface energy on tensile strength. Notable are effects of strong basal texture, which influences average strength via both elastic anisotropy and basal cleavage plane orientation. Effects of loading rate are naturally more prominent for materials that fail mostly intergranularly rather than transgranularly, in agreement with experimental observations.

Microstructures and tribological properties of MoS2 overlayers on MAO Al alloy

To improve tribological properties of micro-arc oxidation (MAO) coating, MoS2 overlayers with self-lubricating effect were prepared by hydrothermal synthesis. The results showed that MoS2/MAO coating was mainly composed of MoS2, γ-Al2O3 and mullite phases. With an increase of hydrothermal temperature, crystallinity, thickness and continuity of the MoS2 overlayer were increased. E2 g/A1 g ratio in the Raman spectra experienced a decrease from 0.738 to 0.493. XPS and TEM analysis discovered that oxygen was incorporated into the MoS2 at lower hydrothermal temperature from incomplete decomposition of MoO42-. Wear tests evidenced a lower average COF and better self-lubricating effect in the MoS2 synthesized at lower temperature. It was concluded that oxygen-incorporation into the MoS2 improved self-lubricating effect due to alignment to basal-plane orientation.

Template-free scalable growth of vertically-aligned MoS2 nanowire array meta-structural films towards robust superlubricity.

Two-dimensional (2D) molybdenum disulfide exhibits a variety of intriguing behaviors depending on its orientation layers. Therefore, developing a template-free atomic layer orientation controllable growth approach is of great importance. Here, we demonstrate scalable, template-free, well-ordered vertically-oriented MoS2 nanowire arrays (VO-MoS2 NWAs) embedded in an Ag-MoS2 matrix, directly grown on various substrates (Si, Al, and stainless steel) via one-step sputtering. In the meta-structured film, vertically-standing few-layered MoS2 NWAs of almost micron length (∼720 nm) throughout the entire film bulk. While near the surface, MoS2 lamellae are oriented in parallel, which are beneficial for caging the bonds dangling from the basal planes. Owing to the unique T-type topological characteristics, chemically inert Ag@MoS2 nano-scrolls (NSCs) and nano-crystalline Ag (nc-Ag) nanoparticles (NPs) are in situ formed under the sliding shear force. Thus, incommensurate contact between (002) basal planes and nc-Ag NPs is observed. As a result, robust superlubricity (friction coefficient μ = 0.0039) under humid ambient conditions is reached. This study offers an unprecedented strategy for controlling the basal plane orientation of 2D transition metal dichalcogenides (TMDCs) via substrate independence, using a one-step solution-free easily scalable process without the need for a template, which promotes the potential applications of 2D TMDCs in solid superlubricity.

Theoretical analysis of interfacial design and thermal conductivity in graphite flakes/Al composites with various interfacial coatings

Abstract Graphite flakes/Al composites are promising thermal management materials due to high thermal conductivity (TC) in basal plane orientation, matched coefficient of thermal expansion, and good machinability. In this article, the acoustic mismatch model and the effective medium approach are applied to predict the influence of different interfacial coatings on the interfacial thermal conductance (ITC) and the TC of graphite flakes/Al composites, respectively. With the increase in the thickness of interfacial coatings, the ITC and the TC of graphite flakes/Al composites decrease. For the composites with Ni, Cr/Cr7C3/Cr3C2, Si/SiC, Ti/TiC, WC, and Mo/Mo2C coatings, the ITC is sensitive to coating thickness. In order to obtain ideal TC of graphite flakes/Al composites, the thickness of the coatings should be controlled below 1 μm. It is reasonable that the TC of the graphite flakes/Al composites increases as the volume fraction of graphite flakes increases. The TC of the graphite flakes/Al composites increases with the ITC and changes slowly when the ITC increases to a certain extent. Si/SiC and WC coatings are proposed to be the most promising candidates to improve the thermal performance of graphite flakes/Al composites.

On the structure-properties relationship of amorphous and crystalline silica nanoparticles reinforced magnesium matrix nanocomposites

In this study, the structure-properties relationship of magnesium matrix nanocomposites was studied. Using an accumulative extrusion (AE) process, the matrix was reinforced by adding 0.25, 0.5 and 1 wt% crystalline and amorphous silica nanoparticles separately. The mechanical behavior of nanocomposite strips was investigated by hardness and uniaxial compression tests. The results indicated that the Mg/0.5%SiO2-Am had the best room temperature compressive properties. An increase of 28.5% in compressive yield strength after extrusion and 235% after annealing was measured. Ultimate compressive strength (UCS) was increased by 20% without reduction in the nanocomposite ductility compared to the pure magnesium strip. FESEM and OM were used for microstructural analysis and revealed no visible cracks or distinct defects between magnesium layers after AE passes. It is found from the EDS analysis that the reinforcement distribution after the AE process was uniform with few agglomerates. Texture analysis using X-ray diffraction and EBSD after the AE process for samples reinforced with 0.5 wt% of amorphous and crystalline silica nanoparticles indicated a negligible difference in the basal plane orientation of the monolithic and nanocomposite magnesium strips after the AE process along extrusion direction. On the other hand, increasing the basal plane peak intensity after annealing for the sample reinforced with amorphous silica compared to the sample reinforced with crystalline silica indicated a weakening of basal texture. Furthermore, the EBSD analysis showed that amorphous silica nanoparticles are more effective than crystalline silica in grain refinement.

THz Radiation Generation Through Graphite Nanoparticles Having Two Different Shapes and Orientations of Basal Planes

Graphite nanoparticles (NPs) in two distinct geometries, i.e., cylindrical and spherical, having two different configurations of their basal planes with respect to the electric field of the laser beam are considered for the terahertz radiation generation with the help of the beating process of two coshyperbolic lasers having frequencies <inline-formula> <tex-math notation="LaTeX">$\omega _{1}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$\omega _{2}$ </tex-math></inline-formula>. Through analytical treatment, we show that a nonlinear ponderomotive force (&#x007E;0.47 dyne) that leads to nonlinear oscillating current is responsible for the radiation generation, when there is a matching of surface plasmon frequency of NPs (longitudinal surface plasmon resonance or transverse surface plasmon resonance) and beating frequency of the lasers (<inline-formula> <tex-math notation="LaTeX">$\omega =\omega _{1}- \omega _{2}$ </tex-math></inline-formula>). A substantial difference of the order of 10³ in the electric field of radiation is seen in the two configurations of NPs, i.e., when their basal planes are parallel or perpendicular to the field of the incident beams. This study also shows that the radiation field can be controlled by changing the geometry of the NPs, and the conversion efficiency is of the order of <inline-formula> <tex-math notation="LaTeX">${10}^{-4}$ </tex-math></inline-formula> in the case of the combined system of cylindrical and spherical NPs.

Hat-Top Beams for Generating Tunable THz Radiations Using a Medium of Conducting Nanocylinders

There are a large number of studies for terahertz (THz) radiation generation, but tunable THz sources are still a challenge since it is difficult to tune frequency, focus and intensity of the radiation simultaneously. The present work proposes the THz generation by the interaction of two hat-top laser beams with a host medium of argon gas containing graphite nanocylinders, as these beams result in highly nonlinear interaction because of a smooth dip in their peak intensity and a fast rise and fall in the overall intensity pattern. Such an interaction produces nonlinear current (6.7 × 108 A/m2) because of the electron cloud of the nanocylinders, which can be modulated by the laser and medium properties for realizing tunable THz radiation. The orientation of basal planes of nanocylinders is shown to be important for this mechanism, though it may be challenging for the experimentalists. The resonant excitation takes place when the plasmon frequency matches the beating frequency of the laser beams, and in the proposed mechanism one can have longitudinal surface plasmon resonance (~12 THz) and transverse surface plasmon resonance (~40 THz), leading to frequency-tunable THz radiation. The role of height and inter particle distance between the adjacent nanocylinders on the THz field amplitude and the efficiency of the mechanism is uncovered by controlling the aspect ratio in the nanocylinders. For example, reducing the inter particle distance from 180 nm to 60 nm leads to the enhancement of THz field from 1 × 108 V/m to 5.48 × 108 V/m. The profile of the emitted THz radiation is investigated in detail under the effect of various parameters in order to prove the practicality of the proposal. The proposed design and mechanism would be attractive for electromagnetic and communication societies which are dealing with millimeter-waves and THz components in addition to its medical application.

Melting, Crystallization, and Alloying Dynamics in Nanoscale Bismuth Telluride.

It is critical to understand the transformation mechanisms in layered metal chalcogenides to enable controlled synthesis and processing. Here, we develop an alumina encapsulation layer-based in situ transmission electron microscopy (TEM) setup that enables the investigation of melting, crystallization, and alloying of nanoscale bismuth telluride platelets while limiting sublimation in the high-vacuum TEM environment. Heating alumina-encapsulated platelets to 700 °C in situ resulted in melting that initiated at edge planes and proceeded via the movement of a sharp interface. The encapsulated melt was then cooled to induce solidification, with individual nuclei growing to form single crystals with the same basal plane orientation as the original platelet and nonequilibrium crystal shapes imposed by the encapsulation layer. Finally, heating platelets in the presence of antimony caused alloying and lattice strain, along with heterogeneous phase formation. These findings provide new insight into important transformation processes in layered metal chalcogenide materials.

Direct observation of the elasticity-texture relationship in pyrolytic carbon via in situ micropillar compression and digital image correlation

Pyrolytic carbon (PyC) plays a critical role in many applications for its unique properties. In ceramic composite systems, the elastic properties of PyC at the fiber/matrix interface drive toughening mechanisms, enabling structural performance at increased operating temperatures. PyC expresses a wide range of crystallographic texture depending on fabrication parameters. As a result, modelling and optimization requires direct understanding of the texture-property relationships at the relevant length scales. This research leverages high-resolution transmission electron microscopy (HRTEM) to link the PyC microstructure to the elastic response observed via digital image correlation (DIC) during micropillar compression. The HRTEM and DIC results quantitatively resolve a gradient for microstructural texture and Young's modulus respectively, showing that disordered texture increases compressive stiffness normal to the average orientation of the PyC basal planes. The values for modulus ranged from 55 to 150 GPa, which are large compared to most experimental methods, but may be more realistic considering the uniaxial stress state and length scale. The behavior supports findings from numerical homogenization models, suggesting that this advanced technique may provide a path forward for optimization and validation of these nanoscale elasticity models.

The role of basal slip in the generation of intergranular stresses in magnesium alloy studied using X-ray diffraction and modelling

Characterisation of the residual stresses at a scale of polycrystalline grains is the main topic of this work. The grazing incidence X-ray diffraction during “in situ” tensile test and a novel method of experimental data interpretation allowed to determine the evolution of macroscopic and intergranular stresses (the second order stresses) during elastic-plastic deformation and elastic unloading of AZ31 alloy sample. Additionally, the values of the critical resolved shear stresses were determined for slip systems activated during plastic deformation.A new important finding of this work is the determination of significant residual intergranular stresses in textured magnesium alloy subjected to plastic deformation. These stresses are correlated with the orientation of basal plane with respect to the applied stress, and they can be explained by a large difference between critical resolved shear stress values for basal and non-basal slip systems. In contrast to the magnesium alloy studied in this work, low values of the second order stresses were found previously in a two-phase Ti alloy due to the small difference between critical resolved stresses in both phases.

Basal-Plane Orientation of Zn Electrodeposits Induced by Loss of Free Water in Concentrated Aqueous Solutions

Concentrated aqueous solutions attract considerable attention because water electrolysis can be suppressed due to a decrease in the amount of free water. The present study focuses on electrodeposition behaviors of metallic zinc (Zn) using concentrated aqueous solutions containing bis(trifluoromethylsulfonyl)amide (Tf2N–) anions. An increase in Tf2N– concentration significantly enhances water-anion interactions, giving characteristic infrared spectra for the breakdown of the hydrogen-bonding networks of water clusters, i.e. loss of free water. For the Tf2N– system Zn electrodeposits with the preferred orientation of hcp basal plane was observed, while, for the SO4 2– system with the presence of the hydrogen-bonding networks, preferred orientation of basal plane was not observed. The preferred orientation of basal plane is not attributed to the adsorption of Tf2N– anions on the electrode, proved by the use of mixed Zn(Tf2N)2-ZnSO4 concentrated solutions. The loss of free water in the concentrated Zn(Tf2N)2 solutions will suppress hydrogen adsorption at the cathode to promote surface diffusion of intermediate Zn+ adions and growth of Zn crystals. Consequently, the promotions and the easier growth of Zn basal planes with the lowest interfacial free energy will enhance the horizontal growth of Zn basal planes.

Significant effect of film thickness on morphology and third-order optical nonlinearities of Cd1−xZnxO semiconductor nanostructures for optoelectronics

The work presented here reported the thickness dependent structural, linear and nonlinear optical properties of nanostructured Cd1−xZnxO thin films. Thin films were prepared with two different thickness (≈ 0.5 µm and 1 µm) by employing a spray pyrolysis (SP) technique for different Zn-doping levels (Cd1−xZnxO with the x value of 0.00, 0.01, 0.05 and 0.1). X-ray diffraction studies confirm the polycrystalline nature having a cubic crystal structure. In terms of an aspect ratio of the columnar structure and dispersion in hexagonal (1 1 1) basal plane orientation, a thickness dependency of structural evolution was discussed. The Scherrer rule was employed to determine the crystallite size and found to be decreased. FESEM images indicate grains which are uniform and grain size slightly increased with an increase in dopant concentration, annealing and thickness of the films, respectively. The optical energy band gap (Eg) of the prepared films was found to be increased from 2.50 to 2.67 eV. The NLO parameters of the samples were measured from the Z-scan data under DPSS continuous wave laser excitation at 532 nm and the results reveal that reverse saturable absorption (RSA) and self-defocusing natures are the attributed and observed nonlinearity of the nanostructures. The third-order NLO components such as β, $$n_{2}$$ and χ(3) are found to be enhanced with one order of magnitude higher with the influence of thickness from 1.25 × 10–4 to 2.47 × 10–3 (cm W−1), 7.08 × 10–9 to 3.35 × 10–8 (cm2 W−1) and 4.06 × 10–7 to 1.96 × 10–6 (esu) respectively. The inspiring results of NLO parameters are also due to the increasing localized defect states on grain boundaries as the film thickness increases, suggesting the prepared films are a promising material for nonlinear photonic device applications.

Interfacial effect between graphite and iron substrate on basal plane orientation and lubricity of graphite

The role of graphite/substrate interface in low-friction behavior of graphite was investigated. Iron and graphite powder mixtures were plastically deformed in either Ar–H2 or air atmospheres to obtain bare iron or iron oxide surface. Then, graphite particles adhered to and formed interfaces with surfaces. Friction force microscopy revealed that friction on particle surface milled in Ar–H2 atmosphere was obviously higher. X-ray absorption near-edge structure and transmission electron microscopy revealed that although the basal plane of graphite oriented along the oxidized surface, it did not occur along the bare iron surface, which explains the difference in lubricity on each surface.

Effects of microstructure on the torsional properties of biodegradable WE43 Mg alloy

Torsional properties are important performance parameters for bone screw applications, but they are seldom studied, especially for newly developed biodegradable Mg alloys. In this study, WE43 Mg alloy with different microstructures was achieved by equal channel angular pressing (ECAP) and heat treatment, and their torsional properties were studied. In addition, tensile properties were also tested as a comparison. The results indicated that grain refinement led to higher torsional strength and ductility, while the second phases improved the torsional strength but reduced the ductility. The texture was strengthened after ECAP, as a result the tensile strength increased, but the torsional strength did not increase and even decreased, especially for 2-pass ECAP sample with a typical basal fiber texture. The basal plane orientation deviation from the extrusion direction after 4-pass ECAP resulted in higher torsional strength and lower torsional ductility, but lower tensile strength and higher tensile ductility were obtained. This implied that a strong fiber texture would reduce the torsional strength but improve the torsional ductility, which was different from its effect on tensile properties.

The morphological effect of carbon fibers on the thermal conductive composites

The locally-exact homogenization theory (LEHT) with thermal conductive capability is developed to investigate the morphological effect of carbon/graphite fibers on the effective and localized thermal responses of periodic composites. Based on the orientations of basal planes, the material properties of carbon fibers can be transversely isotropic, radially orthotropic or circumferentially orthotropic, possibly influencing the microscopic behavior of thermal conductive composites. By taking fiber-fiber interactions into account, repeating unit cells (RUCs) of hexagonal and rectangular geometries are considered with large fiber volume fractions. The efficiency and stability of the LEHT are guaranteed by solving the complete internal eigenvalue functions, imposing point-wise continuity conditions, as well as implementing the generalized variational principle. It is demonstrated that the present theory exhibits good agreement with the independently developed Eshelby solutions and Hashin's formula. The morphological effects are also tested by generating effective coefficients over a wide range of fiber volume fractions and recovering the local thermal field concentrations within the composite microstructures. The results clearly indicate that even if the homogenized properties are not significantly affected by the morphologies of carbon fibers by satisfying the replacement scheme, the large heat-flux gradients within the orthotropic fibers could still lead to the split of carbon reinforcement.

Effect of texture evolution on corrosion resistance of AZ80 magnesium alloy subjected to applied force in simulated body fluid

The electrochemical corrosion behavior of a rolled AZ80 magnesium alloy after pre-compressive strain along different orientation in a simulated body fluid (SBF) was investigated by immersion test for 48 h. The results showed that the corrosion resistance is related to the crystal texture of the material. The texture evolution induced by plastic deformation changed the corrosion behavior of the magnesium alloy. Slip and twin associated with plastic deformation changed the orientation of crystallographic planes. The surface containing highly concentrated orientation of (0002) basal plane has higher corrosion resistance. The appearance of tension twinning could improve the corrosion resistance of magnesium alloy with specific orientation. However, the coexistence of tension twinning with high volume fraction and slip with high density dislocation reduced the corrosion resistance and corrosion anisotropy of the magnesium alloy.

Microstructure, texture, and strain-hardening behavior of extruded Mg–Gd–Zn alloys

The effect of Zn content on the microstructure, texture, mechanical properties and strain-hardening behavior of extruded Mg–2Gd–xZn (x = 0, 1, 2 and 3 wt%) sheets was investigated. Evaluation of texture revealed that while all of the alloys exhibited weak textures, the texture component was altered from a basal to a non-basal one by the addition of Zn. A typical transverse direction (TD) split texture with basal poles rotated about 40° from the normal direction (ND) toward TD was observed for the Zn-containing alloys, the effect being more pronounced at higher Zn contents. Furthermore, the Mg–2Gd–1Zn alloy exhibited the weakest texture due to solute drag imposed by co-segregation of Zn and Gd atoms at grain boundaries. Addition of Zn also resulted in a general increase in yield stress, ultimate tensile strength and elongation along the extrusion direction from 99 to 172 MPa, 178 to 263 MPa, and 25 to 35% for Mg–2Gd and Mg–2Gd–3Zn alloys, respectively. However, increasing Zn content was accompanied by an initial decrease in anisotropy of mechanical properties and strain-hardening behavior, followed by an increase at higher Zn contents. This was due to the difference of orientation of basal planes with regard to tension direction. As a result, lower yield stress, higher elongation and strain-hardening capacity was obtained along TD (with higher Schmid factor for basal slip) compared to ED. It was concluded that excellent mechanical properties and low anisotropy can be achieved in the Mg–2Gd–1Zn alloy.