N-type Doping Research Articles

Investigation of Phosphorus Spin on Dopant on SOI Wafer

Silicon on insulator (SOI) wafer has allowed the integrated circuit (IC) industry to create superior, high-performance solutions. In addition, doping techniques are vital in the silicon sector due to the need to regulate the material electrical properties. The spin on dopant (SOD) approach is an alternative method that involves spinning a solution containing dopant onto SOI wafers. This research aims to determine the impact of thermal diffusion temperature and soaking time on sheet resistance of doped SOI wafer using SOD approach. Additionally, the homogeneity of doping was studied by utilizing mapping techniques. Three inches boron-doped SOI wafers were cut and cleaned according to Radio Corporation of America (RCA) standards. N-type dopants of Filmtronics SOD P509 were deposited on SOI wafer by using a spin coater, for 40 seconds at 4,000 revolutions per minute (rpm). The thermal diffusion temperature and soaking time were set between 700°C to 1000°C for 30 to 120 minutes. After thermal diffusion, hydrofluoric acids (HF) were diluted and used to etch samples. All materials were evaluated using a four-point probe, Hall Effect and Atomic Force Microscope (AFM). The results show that when the thermal diffusion soaking time increases, sheet resistance decreases until activated dopants are saturated. When sheet resistance decreases, dopant concentration rises. Temperature and soaking time increase carrier density and surface roughness, while decreasing Hall mobility. From mapping techniques, it shows low non-uniformity value which less than 10% suggests good thermal diffusion control.

First-principles study on the lattice dynamics, electronic, mechanical, and thermoelectric properties of half-heusler compounds TiXSn (X = Ni, Pd, Pt)

The rapid depletion of fossil fuels and their environmental impact can be mitigated through the exploration of efficient and sustainable materials capable of converting waste heat into electrical energy. Half-Heusler compounds are considered highly promising materials in the field of thermoelectric applications. In this study, utilizing semi-classical Boltzmann transport theory and deformation potential theory, we investigate the electronic structure, mechanical properties, and thermoelectric performance of TiXSn (X = Ni, Pd, Pt) compounds. Our results indicate that TiXSn (X = Ni, Pd, Pt) compounds are indirect bandgap semiconductors. All three compounds are ductile materials. p-type doping in TiXSn (X = Ni, Pd, Pt) compounds demonstrates better thermoelectric performance than n-type doping. At 300 K, the lattice thermal conductivity of TiPdSn is as low as 5.25 Wm−1K−1. Moreover, at 900 K, the maximum ZT values for p-type TiNiSn, TiPdSn, and TiPtSn are 0.56, 0.59, and 0.70, respectively, suggests that p-type TiXSn (X = Ni, Pd, Pt) compounds have promising thermoelectric applications.

Thermoelectric Properties of N-type Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>x</sub>SbBi Materials Doped with La and Mn

Mg<sub>3</sub>Sb<sub>2</sub>-based n-type materials are consisted of earth-abundant elements and possess comparable thermoelectric properties with n-type Bi<sub>2</sub>Te<sub>3</sub> at low temperatures, which make them promising candidates for cooling and power generation applications in terms of cost and performance. Substitution of Sb atom with chalcogen elements (Te, Se S) is a conventional method for n-type doping, but doping cations such as rare-earth elements and transition metals is also widely studied for its unique advantages. In this study, La and Mn were selected for co-doping of Mg3SbBi, and the thermoelectric performances of the doped materials were investigated. Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>x</sub>SbBi (0  <i>x</i>  0.015) polycrystalline samples were made by sintering the fine powders of the mother alloy after arc melting, in which elemental Mn and LaSb compound were included for n-type dual doping. Considering the loss of Mg at elevated temperatures by vaporization, the molar ratio of Mg, Sb, and Bi in the mixture for arc melting was set to 4 : 1 : 1 with excess Mg. Analysis shows that all the samples are n-type, and the electrical conductivity of Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>0.015</sub>SbBi increased by 62% from the Mn-free Mg<sub>3</sub>La<sub>0.005</sub>SbBi at 298 K. In addition, the lattice thermal conductivity (<i><sub>lat</sub></i>) decreased with increasing Mn content in the measured temperature range of 298-623 K. The minimum value of <i><sub>lat</sub></i> was about 0.60 W m<sup>-1</sup>K<sup>-1</sup> in Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>0.015</sub>SbBi at 523 K, which is about 19% smaller than that of the Mn-free sample. As a result of these enhancements in thermoelectric performance, the maximum figure of merit (<i>zT<sub>max</sub></i>) of 1.12 was obtained in Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>0.01</sub>SbBi and Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>0.015</sub>SbBi at 573 K, and the <i>zT</i> at 298 K increased by 73% to 0.35 in Mg<sub>3</sub>La<sub>0.005</sub>Mn<sub>0.015</sub>SbBi compared to Mn-free Mg<sub>3</sub>La<sub>0.005</sub>SbBi, which is beneficial to room-temperature applications.

Interface Properties of MoS2 van der Waals Heterojunctions with GaN.

The combination of the unique physical properties of molybdenum disulfide (MoS2) with those of gallium nitride (GaN) and related group-III nitride semiconductors have recently attracted increasing scientific interest for the realization of innovative electronic and optoelectronic devices. A deep understanding of MoS2/GaN interface properties represents the key to properly tailor the electronic and optical behavior of devices based on this heterostructure. In this study, monolayer (1L) MoS2 was grown on GaN-on-sapphire substrates by chemical vapor deposition (CVD) at 700 °C. The structural, chemical, vibrational, and light emission properties of the MoS2/GaN heterostructure were investigated in detail by the combination of microscopic/spectroscopic techniques and ab initio calculations. XPS analyses on as-grown samples showed the formation of stoichiometric MoS2. According to micro-Raman spectroscopy, monolayer MoS2 domains on GaN exhibit an average n-type doping of (0.11 ± 0.12) × 1013 cm-2 and a small tensile strain (ε ≈ 0.25%), whereas an intense light emission at 1.87 eV was revealed by PL analyses. Furthermore, a gap at the interface was shown by cross-sectional TEM analysis, confirming the van der Waals (vdW) bond between MoS2 and GaN. Finally, density functional theory (DFT) calculations of the heterostructure were carried out, considering three different configurations of the interface, i.e., (i) an ideal Ga-terminated GaN surface, (ii) the passivation of Ga surface by a monolayer of oxygen (O), and (iii) the presence of an ultrathin Ga2O3 layer. This latter model predicts the formation of a vdW interface and a strong n-type doping of MoS2, in closer agreement with the experimental observations.

Structural and optical properties of phosphorous doped nanocrystalline silicon deposited using a VHF PECVD process for silicon heterojunction solar cells and optimization of a simple p-n junction cell using SCAP-1D tool.

Initially hydrogenated silicon (Si:H) thin films have been deposited using a plasma-enhanced chemical vapor deposition technique (PECVD) using silane (SiH4) as a precursor gas diluted in an inert gas argon (Ar) environment. Subsequently phosphine gas (PH3) was used as the n-type dopant and the deposition was carried out at a fixed substrate temperature of 200 °C. The PH3 flow rate was varied in the range of 0-1 sccm. The effect of PH3 flow rates on optical, electrical, and structural properties of hydrogenated amorphous and micro/nanocrystalline silicon films has been investigated and detailed analysis is presented. These films may find application in heterojunction solar cells as an emitter layer. Further, a crystalline silicon (c-Si) based simple p-n junction solar cell is simulated using an SCAP-1D tool to observe the effect of layer thickness and doping density on solar cell parameters.

Electrical properties and structural optimization of GaN/InGaN/GaN tunnel junctions grown by molecular beam epitaxy

The InGaN films and GaN/InGaN/GaN tunnel junctions (TJs) were grown on GaN templates with plasma-assisted molecular beam epitaxy. As the In content increases, the quality of InGaN films grown on GaN templates decreases and the surface roughness of the samples increases. V-pits and trench defects were not found in the AFM images. p++-GaN/InGaN/n++-GaN TJs were investigated for various In content, InGaN thicknesses and doping concentration in the InGaN insert layer. The InGaN insert layer can promote good interband tunneling in GaN/InGaN/GaN TJ and significantly reduce operating voltage when doping is sufficiently high. The current density increases with increasing In content for the 3 nm InGaN insert layer, which is achieved by reducing the depletion zone width and the height of the potential barrier. At a forward current density of 500 A/cm2, the measured voltage was 4.31 V and the differential resistance was measured to be 3.75 × 10−3 Ω·cm2 for the device with a 3 nm p++-In0.35Ga0.65N insert layer. When the thickness of the In0.35Ga0.65N layer is closer to the “balanced” thickness, the TJ current density is higher. If the thickness is too high or too low, the width of the depletion zone will increase and the current density will decrease. The undoped InGaN layer has a better performance than n-type doping in the TJ. Polarization-engineered tunnel junctions can enhance the functionality and performance of electronic and optoelectronic devices.

In-situ methyl red doped MoS2 field effect transistor made by atomically thin MoS2 channel

Here we present the effects of Methyl Red (MR) doping on the electrical properties of the MoS2 field effect transistor (FET) in in-situ experimental system where the doping and electrical measurement are carried out in a single ultra-high vacuum chamber. A single-layered MoS2 flake was used as channel material for the FET preparation. N-type doping by MR was confirmed by the left shift of threshold voltage (Vth) and the surface vibrational change measured by Raman spectroscopy. The n-doping by MR is implied by the Fermi level shift towards greater binding energy with MR coverage, as proven by an X-ray photoelectron spectroscopy (XPS) measurement. It is estimated from XPS that the MoS2-FET device may detect the doping effect from the sub-monolayer MR. MR was detected on the MoS2 surface by the Time-of-Flight Secondary Ionization Mass Spectroscopy (ToF-SIMS). The findings may pave the way for innovations in electronic device design, with potential implications for fields ranging from nanoelectronics to sensor technology.

Enhancement of the charge-generation efficiency for a naphthalene diimide-based polymer semiconductor by using a pyrene-substituted n-dopant

A new n-type dopant featuring a pyrene unit was developed, which shows better charge-generation efficiency for a naphthalene diimide (NDI)-based conjugated polymer than N-DMBI due to the distinctive interaction between the pyrene and the NDI units.

Charge transfer in superbase n-type doping of PCBM induced by deprotonation.

N-type electronic doping of organic semiconductors (OSCs) by using superbase compounds shows high doping efficiency (H. Wei, Z. Cheng, T. Wu, Y. Liu, J. Guo, P.-A. Chen, J. Xia, H. Xie, X. Qiu, T. Liu, B. Zhang, J. Hui, Z. Zeng, Y. Bai and Y. Hu, Adv. Mater. 2023, 35, 2300084). While a deprotonation reaction is believed to trigger the doping process, the detailed mechanism therein is not yet fully understood. In the present work we theoretically study the electronic structure of the deprotonated Phenyl-C61-butyric acid methyl ester (PCBM) molecule, as well as the charge transfer (CT) between PCBM and its deprotonated species. We find that deprotonated PCBM without formation of a new bond between the deprotonated side chain and fullerene induces electronic structure with broken spin symmetry, where an in-gap state is singly occupied by an unpaired electron. A second scenario that we find to be possible is the formation of a new bond between the deprotonated side chain and a fullerene. This leads to a spin symmetric electronic structure with partially localized in-gap state, which is expected to contribute less to the effective doping. These results show that the deprotonated PCBM species without new bond formation predominantly accounts for the effective n-type doping of PCBM, an insight that will be useful for optimization of this recently discovered doping method.

Unraveling the atomic mechanism of the disorder–order phase transition from γ-Ga2O3 to β-Ga2O3

In this paper, we employ in situ transmission electron microscopy to study the disorder–order phase transition from amorphous Ga2O3 to γ-Ga2O3 and then to β-Ga2O3. The in situ studies are complemented by ex situ annealing experiments, of which the results are analyzed by x-ray diffraction and high resolution (scanning) transmission electron microscopy. Amorphous Ga2O3 deposited at 100 °C by molecular beam epitaxy crystallizes at 470 °C in the γ phase (Fd3̄m), which undergoes a phase transition to the β phase above 500 °C. Between 500° and 900 °C, we find a mixture of γ-Ga2O3 and β-Ga2O3 coexisting. Above 950 °C, we find only β-Ga2O3. Through our analyses and by considering symmetry relations, we have constructed a coincidence site lattice of both structures containing a common fcc-type sublattice occupied by oxygen atoms, the cation sites of β-Ga2O3 common to both phases, and partially occupied cation sites in the γ phase corresponding to the interstitial sites in the β phase. We assign the atomic displacements within this lattice responsible for transforming the initially disordered spinel structure with partially occupied cation sites into the well-ordered lattice of β-Ga2O3. We identify this transition as a reconstructive disorder-to-order phase transition, mediated by the exchange of cations to next nearest neighbor sites. Our model not only explains recent observations of the formation of γ-Ga2O3 during implantation for n-type doping and the subsequent recovery of β-Ga2O3 following annealing but also holds potential for inspiring understanding in other materials with similar phase transitions.

A promising high temperature 2D thermoelectric material: novel single-layer ZrHfS4.

Based on the first-principles calculation and Boltzmann transport theory, we report the discovery of a promising candidate for high-performance two-dimensional (2D) thermoelectric material: the single-layer (1L) ZrHfS4. Through the first-principles molecular dynamics simulation and phonon calculation, 1L-ZrHfS4 is predicted to be thermodynamically stable even at high temperatures. In addition, the lattice thermal conductivity of 1L-ZrHfS4 is calculated to be 10.2 W m-1 K-1, which is smaller than that of 2D transition-metal dichalcogenides, such as MoS2 and WS2. Notably, considering not only all the transport coefficients but also the relaxation time for both acoustic and optical phonon scattering, the maximum figure of merit (ZT) of 1L-ZrHfS4 at 1200 K can achieve 1.92 at moderate n-type doping. These findings suggest 1L-ZrHfS4 as a potential material for efficient thermoelectric energy conversion, particularly in applications requiring high temperature operation.

Theoretical insights into the structural, electronic and thermoelectric properties of the inorganic biphenylene monolayer.

Being motivated by a recently synthesized biphenylene carbon monolayer (BPN), using first principles methods, we have studied its inorganic analogue (B-N analogue) named I-BPN. A comparative study of structural, electronic and mechanical properties between BPN and I-BPN was carried out. Like BPN, the stability of I-BPN was verified in terms of formation energy, phonon dispersion calculations, and mechanical parameters (Young's modulus and Poisson's ratio). The chemical inertness of I-BPN was also investigated by adsorbing an oxygen molecule in an oxygen-rich environment. It has been found that the B-B bond favours the oxygen molecule to be adsorbed through chemisorption. The lattice transport properties reveal that the phonon thermal conductivity of I-BPN is ten times lower than that of BPN. The electronic band structure reveals that I-BPN is a semiconductor with an indirect bandgap of 1.88 eV, while BPN shows metallic behaviour. In addition, we investigated various thermoelectric properties of I-BPN for possible thermoelectric applications. The thermoelectric parameters, such as the Seebeck coefficient, show the highest peak value of 0.00289 V K-1 at 300 K. Electronic transport properties reveal that I-BPN is highly anisotropic along the x and y-axes. Furthermore, the thermoelectric power factor as a function of chemical potential shows a peak value of 0.057 W m-1 K-2 along the x-axis in the p-type doping region. The electronic figure of merit shows a peak value of approximately unity. However, considering lattice thermal conductivity, the peak value of the total figure of merit (ZT) reduces to 0.68(0.46) for p-type and 0.56(0.48) for n-type doping regions along the x(y) direction at 900 K. It is worth noting that our calculated ZT value of I-BPN is higher than that of many other reported B-N composite materials.

Thermoelectric Properties of Mg3(Bi,Sb)2 under Finite Temperatures and Pressures: A First-Principles Study.

Mg3Bi2-vSbv (0 ≤ v ≤ 2) is a class of promising thermoelectric materials that have a high thermoelectric performance around room temperatures, whereas their thermoelectric properties under pressures and temperatures are still illusive. In this study, we examined the influence of pressure, temperature, and carrier concentration on the thermoelectric properties of Mg3Bi2-vSbv using first-principle calculations accompanied with Boltzmann transport equations method. There is a decrease in the lattice thermal conductivity of Mg3Sb2 (i.e., v = 2) with increasing pressure. For a general Mg3Bi2-vSbv system, power factors are more effectively improved by n-type doping where electrons are the primary carriers over holes in n-type doping, and can be further enhanced by applied pressure. The figure of merit (zT) exhibits a positive correlation with temperature. A high zT value of 1.53 can be achieved by synergistically tuning the temperature, pressure, and carrier concentration in Mg3Sb2. This study offers valuable insights into the tailoring and optimization of the thermoelectric properties of Mg3Bi2-vSbv.

Effects of substitutional doping CsSn0.75A0.25I3 (A=B, Sb) in the thermoelectric properties of the B-γ phase from first principles

Among hybrid and all-inorganic halide perovskites, CsSnI3 has stood out with moderate electrical conductivity and ultralow thermal conductivity. Nevertheless, the former is still low compared to values of traditional thermoelectric materials, this makes its applications scarce. Herein, we wish to present a DFT study combined with the application of the Boltzmann transport equation, to determine the effects of p and n-type substitutional doping in the lattice structure, electronic and thermoelectric properties of CsSn0.75A025I3 (A = B, Sb). Our calculations show that doping increases the thermoelectric power factor to 181.2 µW m−1 K−2 under Sb-doping, which represents a twofold value compared to 78.3 µW m−1 K−2 of the pristine lattice; under B-doping we obtained a value of 145.6 µW m−1 K−2. CsSnI3 has higher power factor upon n-type doping. Finally, yet importantly, we further examine the shifts in the Fermi level using the effective mass model framework. In doing so, our work predicts a performance enhancement by achieving a Fermi energy level close to the VBM, or CBM. Similarly, our work demonstrates that doping represents an effective way to improve the thermoelectric power factor of CsSnI3, this being attributed to the increase of charge carriers and the modification of the band structure.

(Invited) Towards GaN-on-GaN High-Power Electronic Devices

Application of gallium nitride (GaN) substrates in electronic and optoelectronic industries is constantly increasing. In order to fabricate wafers, GaN crystals of the highest structural quality and desired electrical (and sometimes optical) properties must be grown. Today, there are three main GaN crystallization methods: i/ halide vapor phase epitaxy (HVPE) with its derivatives: halide-free VPE and oxide VPE; ii/ sodium-flux; and iii/ ammonothermal. The last approach can be basic or acidic depending on what mineralizer is used to increase the solubility of GaN in the feedstock zone. In this paper we will focus on HVPE and basic ammonothermal growth of GaN [1]. Not only bulk growth will be presented. The HVPE method will also be discussed as the best method to crystallize the drift layers necessary for high-power vertical electronic devices (FET transistors, Schottky diodes).One of the best methods for introducing dopants into semiconductors is ion implantation. The introduced structural damage can be removed by a proper annealing process. The high-temperature treatment enables also electrical and/or optical activation of the implanted dopants. In the case of GaN, annealing at high temperature (~1300°C - 1400°C) seems difficult. This compound loses its thermodynamic stability slightly above 800°C at atmospheric pressure. At higher temperature the crystal will decompose. One of the solutions is to anneal GaN at high nitrogen (N2) pressure. Such technology is called ultra-high-pressure annealing (UHPA) [2]. In this paper, application of UHPA for GaN crystals and layers implanted by different ions (acceptors and donors) will be presented. The latest results of the implantation with magnesium (Mg), beryllium (Be), zinc (Zn), and calcium (Ca) ions into GaN in order to obtain p-type conductivity will be discussed [3,4]. Silicon (Si) implantation into GaN for n-type doping will also be analyzed. Structural, electrical and optical properties of implanted GaN after UHPA will be discussed in terms of application for GaN-based devices.A kV class, low ON-resistance, vertical GaN junction barrier Schottky (JBS) diode with selective-area p-regions formed via Mg implantation followed by high-temperature, ultra-high pressure post-implantation activation anneal without a capping layer was already demonstrated [5]. The forward characteristics of the JBS diode showed ideality factor (n) 1.03, turn-on voltage (VON) 0.75 V, current ON/OFF ratio (at ±3 V) ~1011, and specific differential ON-resistance (RON) 0.6 mΩ·cm2. The breakdown voltage of the JBS diode was 915 V.

Synthesis and characterization of niobium carbide thin films on diamond surface for superconductive application

Diamond's unique properties make it attractive for use in a variety of industrial applications. However, this material has not found mass application in microelectronics due to several factors, including the lack of large-sized plates, n-type doping, and high-quality metallization. In this article, we address the problem of diamond surface metallization by forming niobium carbide layers. We obtained a niobium carbide film several nanometers thick that exhibits superconducting behavior up to 12.4 K. To our knowledge, this is the highest superconducting transition temperature achieved in the niobium carbide system. The crystal lattice parameter of the film is 4.4659 Å, which is close to the maximum value for niobium carbide lattice parameters. Density functional theory calculations were employed to investigate the thermodynamic stability of niobium carbide compounds at various temperatures and determine the superconducting critical temperature of niobium carbide. The combination of diamond's high thermal conductivity, along with the strong adhesion and superconductivity of niobium cabide films, introduces exciting possibilities for the realization of superconductive sensitive detectors.

Design of a lateral photoconductive semiconductor switch with a low resistivity region on semi-insulating GaN to enhance breakdown characteristics

The breakdown characteristics of the semi-insulating lateral GaN photoconductive semiconductor switches (PCSS) with low resistivity region (LRR) structure were simulated. The design, which can reduce the peak electric field by adjusting the electric field distribution for PCSS, was first proposed. In comparison to conventional field plate and n-type doping below the electrode structures, the LRR structure robustly enhances the breakdown characteristics of PCSS while reducing the influence of on-state characteristics. The impact of different structural parameters on the breakdown voltage and on-state characteristics was investigated. In the case of a small size device with a 5 μm electrode gap, the LRR structure is able to decrease the peak electric field by 54 % at 400 kV/cm and increase breakdown voltage by 45 %. When the electrode gap is increased to 0.25 mm, under a bias voltage of 5 kV, the field plate structure can reduce the peak electric field by 35 %, but the LRR structure can reduce the peak electric field by 42 %. When applied a voltage of 2 kV, the PCSS with the LRR structure triggered by a laser pulse with a wavelength of 532 nm and an energy of 265 μJ has a minimum on-resistivity being less than 0.5 Ω cm and the resistivity ratio between the off and on states reaching up to 1 × 108.

Decomposed defect formation energy for analysis of doping process: The case of n-type and p-type doping of β-FeSi2

Defect formation energy governs the thermodynamics of a specific dopant within the host material. Here, we introduce an approach to decomposing the defect formation energy into intuitive components, each representing a distinct physical step in the process of defect formation. Through this approach, we illustrate that adhering solely to conventional criteria, such as ionic radius, may overlook potential dopants. Taking β-FeSi2, a promising high-temperature thermoelectric material, as an example, we demonstrate that non-intuitive chemical interactions can play a more significant role in lowering the defect formation energy. As a result, Ir on Fe site is found to exhibit unexpected low defect formation energy among the 26 candidate dopants and has been employed in experiment to enhance the thermoelectric figure of merit of n-type β-FeSi2. The understanding gained from this work could be of general interest for addressing the doping limit issue for other potential thermoelectric materials.

On-water surface synthesis of electronically coupled 2D polyimide-MoS2 van der Waals heterostructure

The water surface provides a highly effective platform for the synthesis of two-dimensional polymers (2DP). In this study, we present an efficient on-water surface synthesis of crystalline monolayer 2D polyimide (2DPI) through the imidization reaction between tetra (4-aminophenyl) porphyrin (M1) and perylenetracarboxylic dianhydride (M2), resulting in excellent stability and coverage over a large area (tens of cm2). We further fabricate innovative organic-inorganic hybrid van der Waals heterostructures (vdWHs) by combining with exfoliated few-layer molybdenum sulfide (MoS2). High-resolution transmission electron microscopy (HRTEM) reveals face-to-face stacking between MoS2 and 2DPI within the vdWH. This stacking configuration facilitates remarkable charge transfer and noticeable n-type doping effects from monolayer 2DPI to MoS2, as corroborated by Raman spectroscopy, photoluminescence measurements, and field-effect transistor (FET) characterizations. Notably, the 2DPI-MoS2 vdWH exhibits an impressive electron mobility of 50 cm2/V·s, signifying a substantial improvement over pristine MoS2 (8 cm2/V·s). This study unveils the immense potential of integrating 2D polymers to enhance semiconductor device functionality through tailored vdWHs, thereby opening up exciting new avenues for exploring unique interfacial physical phenomena.

Engineering the electromagnetic response and thermoelectric performance of half-functionalized stanene with [formula omitted], [formula omitted], [formula omitted], [formula omitted] and [formula omitted

We report on, for the first time, a combined density functional theory and Boltzmann-semiclassical calculations of two-dimensional stanene half-passivated with X=H,F,Cl,Br and I The thermodynamical stability is examined through the comparison of the formation energy as well as the analysis of the phonon dispersion spectrum indicating a possible experimental fabrication of these stanene derivatives. Interestingly, using generalized gradient approximation (GGA), the obtained results show that half-iodination and half-hydrogenation induce a half metallic ferromagnetic character and the magnetic moment on the unsaturated Sn atoms are 0.41μB and 0.38μB for SnSn–H and SnSn–I respectively, whereas half-decoration with fluorine, chlorine and bromine adsorbates, characterized with high electronegativity, gives rise to antiferromagnetic metallic systems. Except SnSn–I, the critical temperatures of the stanene derivatives are above room temperature. These results suggest that magnetism of stanene can be tuned by different passivation atoms. The transport properties, which result in a thermoelectric figure of merit (ZT), are very sensitive to the doping type however, less affected by the temperature variation. The highest ZT value of 0.99 is recorded for the SnSn–H conformer, while it decreases with the increase of the electronegativity. For the four compounds, the maximum figure of merit and seebeck coefficients are located at n-type doping, suggesting that these materials can be strong candidates among n-type materials for thermoelectric applications in high-temperature regions. Our findings demonstrate that half passivation with X-atoms is a feasible method to tune the properties of stanene for spin injection applications and thermoelectric cooling industry.