Film Growth Conditions Research Articles

Optimization of Ti2O3 thin films by magnetron sputtering and study of their photoelectric performance

AbstractAbstractIn this study, Ti2O3 thin films were successfully produced using magnetron sputtering. Through orthogonal gradient experiments, the impact of substrate temperature, sputtering vacuum, RF power, and sputtering duration on surface morphology, roughness, physical structure, and resistivity was investigated. Various analytical techniques were employed, including AFM and SEM for surface morphology observation, XRD and Raman for qualitative physical structure analysis, XPS for elemental valence examination, and the four‐probe method for resistivity measurements. The study identified optimal growth conditions for Ti2O3 films, demonstrating a low resistivity of 2.66 × 10−3 Ω cm under the following conditions: RF power of 200 W, sputtering vacuum of .6 Pa, substrate temperature of 600°C, and sputtering duration of 60 min. Additionally, the sensor arrays were efficiently fabricated using the Lift‐off method to evaluate the photoelectric performance of the films. A light responsiveness of approximately 6 µA/W was observed in the device when illuminated with 950 nm light for 10 s. This finding carries important implications for the use of Ti2O3 thin films in future photoelectric devices.

Magnetic compensation in sputtered ferrimagnetic Mn 4−x Ga x N thin films

Fully compensated ferrimagnets are attracting increasing attention for spintronics. Here we report a series of Mn 4−x Ga x N ferrimagnetic thin films grown on (100)-oriented MgO by magnetron sputtering. A small tetragonal distortion with c/a = 0.99 leads to perpendicular magnetic anisotropy with a [001] easy axis. The magnetisation decreases with increasing Ga content up to x = 0.18, where the magnetic moment is close to zero at room temperature. It increases with further increase of x, indicating the magnetic compensation composition has been crossed and the dominant sublattice has switched from Mn on the corner sites, where it is progressively replaced by nonmagnetic Ga, to noncollinear Mn on the face-centered sites. Compensation found at 235 K in a remanent scan of the x = 0.18 film is confirmed by measurements of the anomalous Hall effect and interpolation of the inverse coercivity. This work establishes the conditions for thin film growth of Mn 4−x Ga x N that could be used for room-temperature ferrimagnetic spintronics. The behaviour of thin films is compared with that of bulk material.

Impact of hydrogenation on the stability and mechanical properties of amorphous boron nitride

Interconnect materials with ultralow dielectric constant, and good thermal and mechanical properties are crucial for the further miniaturization of electronic devices. Recently, it has been demonstrated that ultrathin amorphous boron nitride (aBN) films have a very low dielectric constant, high density (above 2.1 g cm−3), high thermal stability, and mechanical properties. The excellent properties of aBN derive from the nature and degree of disorder, which can be controlled at fabrication, allowing tuning of the physical properties for desired applications. Here, we report an improvement in the stability and mechanical properties of aBN upon hydrogen doping. With the introduction of a Gaussian approximation potential for atomistic simulations, we investigate the changing morphology of aBN with varying H doping concentrations. We found that for 8 at% of H doping, the concentration of sp 3-hybridized atoms reaches to a maximum which leads to an improvement of thermal stability and mechanical properties by 20%. These results will be a guideline for experimentalists and process engineers to tune the growth conditions of aBN films for numerous applications.

Optical characterizations of GaN/MoS2 van der Waals heterojunctions with different band alignments

The integration of gallium nitride (GaN) with 2D molybdenum disulfide (MoS2) to form GaN/MoS2 semiconductor heterojunctions will have high potential applications in novel electronics and optoelectronics. In this study, GaN thin films were grown on pulse-laser-deposited MoS2 layer by plasma-assisted MBE at different substrate temperatures (500 °C, 600 °C and 700 °C, respectively). The energy-band alignments of GaN/MoS2 semiconductor heterostructures were analyzed by X-ray photoelectron spectroscopy. The epitaxial growth conditions of GaN films influenced the band alignment of GaN/MoS2 heterojunction. Type-I heterostructure, a straddling relation between narrow-bandgap MoS2 and wide-bandgap GaN, was observed at the optimized growth temperature of 600 °C. At the same time, photoluminescence (PL) and photoreflectance spectroscopies were employed to analyze the optical properties of MoS2 and GaN/MoS2 heterostructures. The PL and exciton energy transition of 2D MoS2 layer can be enhanced by the capping layer GaN, especially for type-I band alignment structure.

Sodium chloride-assisted CVD enables controlled synthesis of large single-layered MoS2.

Thin-layer MoS2 has attracted much interest because of its potential in diverse technologies, including electronics, optoelectronics and catalysis these few years. In particular, finding a simple and effective solution for large-scale growth of thin-layer semiconductor nanosheets is a prerequisite for achieving their excellent performance. In this paper, we investigated four different substrates under identical conditions for MoS2 film growth and observed a strong correlation between substrate surface conditions and MoS2 growth. To enhance substrate performance, a low-concentration NaCl water solution (25 mg mL-1) was employed for pre-treating the substrate surface, thereby modifying its initial state. In the chemical vapor deposition (CVD) growth environment, the introduced halide ions served as surface dangling bonds. The pre-treated led to a remarkable 90% increase in the growth rate of MoS2 on the substrate surface, facilitating the production of large monolayer MoS2 sheets (∼200 μm). This growth mechanism further enabled the manufacturing of ultra-large single crystals (∼1 mm). Consequently, our research presents a straightforward and cost-effective approach for the large-scale production of nanosheets. Field-effect transistors (FETs) based on the pre-treated monolayer MoS2 exhibited high mobility (12 cm2 V-1 s-1) and a large on/off ratio (104). Therefore, our research provides a simple and low-cost approach for large-scale production of nanosheets for use in high-quality electronics over large areas.

Structural anisotropy in Sb thin films

Sb thin films have attracted wide interest due to their tunable band structure, topological phases, high electron mobility, and thermoelectric properties. We successfully grow epitaxial Sb thin films on a closely lattice-matched GaSb(001) surface by molecular beam epitaxy. We find a novel anisotropic directional dependence on their structural, morphological, and electronic properties. The origin of the anisotropic features is elucidated using first-principles density functional theory (DFT) calculations. The growth regime of crystalline and amorphous Sb thin films was determined by mapping the surface reconstruction phase diagram of the GaSb(001) surface under Sb2 flux, with confirmation of structural characterizations. Crystalline Sb thin films show a rhombohedral crystal structure along the rhombohedral (211) surface orientation parallel to the cubic (001) surface orientation of the GaSb substrate. At this coherent interface, Sb atoms are aligned with the GaSb lattice along the [1̄10] crystallographic direction but are not aligned well along the [110] crystallographic direction, which results in anisotropic features in reflection of high-energy electron diffraction patterns, misfit dislocation formation, surface morphology, and transport properties. Our DFT calculations show that the preferential orientation of the rhombohedral Sb (211) plane may originate from the GaSb surface, where Sb atoms align with the Ga and Sb atoms on the reconstructed surface. The formation energy calculations confirm the stability of the experimentally observed structures. Our results provide optimal film growth conditions for further studies of novel properties of Bi1−xSbx thin films with similar lattice parameters and an identical crystal structure, as well as functional heterostructures of them with III–V semiconductor layers along the (001) surface orientation, supported by a theoretical understanding of the anisotropic film orientation.

Designing Multidimensional and Interconnected Multi-Element Nanostructures by Exsolution-Self-Assembly in a Complex Concentrated Oxide

Complex concentrated oxides (CCOs) are an emerging material class that includes high-entropy oxide (HEOs) and entropy-stabilized oxides (ESOs), whose unprecedented properties stem from disorder-induced distributions in electronic structure and chemistry caused by stabilizing many-cation (typically > 5) solid solutions [1-2]. Integrating these materials into composites with nanoscale tunability will enable tailored (multi)functionality beyond what is possible in a single phase [3]. Here, we demonstrate a novel, highly extensible approach, exsolution self-assembly (ESA), to realize CCO-based nanocomposite thin films with intricate multi-element nanostructures [4]. Using pulsed-laser deposition (PLD), we selectively reduce cations in a 6-cation model perovskite CCO, inducing defect-interaction-driven exsolution and simultaneous self-assembly of metal nanorods and metal-oxide core-shell nanoparticles, depending on film growth conditions. ESA using a CCO precursor enables novel multielement composite morphologies with finely tuned sub-phase chemical composition that are not possible by conventional exsolution or self-assembly independently. By mapping the distribution of distinct sub-phase structure and chemistry with sub-nanoscale electron microscopy and atom probes, we show that Ellingham's model of cation reducibility predicts nanostructure chemical composition while mass transport via extended defects governs local morphology formation. Importantly for various applications, the electronic conductivity of our nanocomposites exceeds 0.1 S/cm at room temperature, with transport correlated to nanostructure formation primarily through B-site cation mixed valency and site occupancy in the CCO matrix.A correlated analysis using aberration-corrected scanning transmission electron microscopy (STEM) imaging, energy dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS), geometric phase analysis (GPA) strain mapping, atom probe tomography (APT) with 3D mass spectrometry, and X-ray photoemission spectroscopy (XPS) was performed to elucidate the fundamental nanostructure formation mechanisms underlying the highly tailorable synthesis approach. We show that the method achieves uniform bulk exsolution with short process time and is manipulated by tuning readily accessible PLD conditions. Detailed characterization resolved the impact of increasing oxygen vacancy concentration and varying cation reducibility on nanostructure self-assembly. For example, metal nanorods grow from the bottom of the thin film to the top surface, with growth restricted by compressive stress exerted by the matrix in the in-plane direction. Metal-oxide core-shell nanoparticles embedded in the matrix form via seed growth effect triggered by metal nanoparticle formation followed by subsequent reduction of additional mobile cations. This work demonstrates a route towards vast morphological tunability and compositional complexity through nanocomposite design of CCO thin films. Given CCOs’ vast combinatorial space, ESA is expected to be highly extensible via application to novel compositions and crystal structures, with the understanding presented here enabling one to take advantage of chemical complexity in a rational way.

Multimodal Microscopy Characterisation of 2D Materials

Spatial characterisation of transition metal dichalcogenides (TMDCs) is crucial for understanding their optoelectronic properties and optimising film growth conditions. In this work, we present a multimodal microscopy platform combining conventional widefield, Raman, photoluminescence and second harmonic generation imaging for the characterisation of 2D materials.The platform was used to characterise CVD grown WSe2 crystals. Raman imaging identified the presence of both monolayer and multilayer WSe2 through a change in the intensity and position of the E12g / A1g phonon modes. Photoluminescence imaging confirmed the presence of monolayer WSe2 with emission at 780 nm and identified two distinct multilayer regions through changes in the photoluminescence wavelength and intensity. Lastly, second harmonic generation imaging under femtosecond laser excitation was used to obtain the relative growth orientation of the three identified domains in the crystal.Figure 1 highlights Raman imaging of WSe2. (a) Intensity of the E12g / A1g (250 cm-1) Raman band, (b) Peak position of the E12g / A1g (250 cm-1) Raman band, (c) least squares spectral matching revealing three distinct Raman spectral areas, (d) Averaged Raman spectra from areas A, B and C. Figure 1

Tuning microstructure and properties of MoNbTaWZr high entropy alloy films by adjusting the parameters in high power impulse magnetron sputtering

Within this study a series of MoNbTaWZr thin films were synthesized using high power impulse magnetron sputtering (HiPIMS) with varying the deposition parameters: duty cycle from 0.5 to 100 % (i.e. DC magnetron sputtering (DCMS)), Ar pressure from 0.5 to 3 Pa and pulse frequency from 25 to 200 Hz. The structure of the deposited films was analyzed by X-ray diffraction and scanning and transmission electron microscopy. In addition, the electrical resistivity and the residual stress of the films was determined. The influence of the deposition parameter variation on structure and properties of the MoNbTaWZr films is discussed on the established framework of film growth conditions achievable with HiPIMS and DCMS and how they can be influenced by adapting the deposition parameters. The performed work is intended to contribute to a comprehensive understanding about synthesis-structure-property relations for refractory high entropy alloy thin films while using MoNbTaWZr films as a model system.

Influence of thiourea concentration during deposition of a CdS buffer layer on the electric properties of Cu2SnS3 solar cells

The p–n interface state and depletion layer region of solar cells were investigated using electrochemical impedance spectroscopy (EIS) measurements to elucidate the effect of varying thiourea (TU) concentrations in chemical bath deposition (CBD) on the photovoltaic properties of Cu2SnS3 (CTS) solar cells. The photoconversion efficiency (PCE) increased as the TU concentration increased, peaking at 0.16 M and decreasing thereafter. Additionally, the constant phase element-p value, which is indicative of the p–n interface state in CTS solar cells, exhibited a similar trend to that of the PCE of CTS solar cells with increasing TU concentration. The decrease in the PCE was due to the electron recombination that occurred at the p–n interface of CTS solar cells with increasing TU concentrations. Therefore, to improve the PCE of the CTS solar cells, the TU concentration in CBD must be optimized because the p–n interface state is sensitive to changes in the growth conditions of CdS films. By studying the effects on the p–n interface state and depletion layer in CTS solar cells using EIS measurements, useful knowledge can be obtained to increase the PCE of all-sulfide-compound solar cells using n-type CdS films as well as CTS.

Ir Film Structural Properties for TES Application

Iridium films grown by pulsed laser deposition (PLD) show different critical temperatures ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> ), which can be almost twice the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> of the bulk. This difference is related to the thickness and deposition conditions. To understand this effect, we grew different films with different configuration parameters: laser focusing, distance to the Ir target, and deposition time. We then measured the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> and analyzed the film with structural measurements by X-ray diffraction (XRD), looking at a possible correlation with the grain size of the film itself. The work was performed to determine the film growth conditions at which it is possible to obtain predetermination of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> with good accuracy using XRD pattern characteristics of Ir films.

ALD deposited bipolar HfOx films for silicon surface passivation

Hafnium oxide thin films consist of trap states which can degrade or enhance the device performance depending upon the application. These trap states play a crucial role in silicon surface passivation when using HfOx films. This paper investigates the dependence of crucial surface passivation parameters on different film growth components of thermal ALD process. Our study is focused on understanding different oxide charges present at the HfOx/Si interface using capacitance-voltage and constant voltage stress studies; particularly trap states introduced during thermal atomic layer deposition process. This study is performed for different film growth conditions to understand the origin of traps states. We show that the interfacial layer (IL) grows during the film deposition and therefore two interfaces are formed, i.e., HfOx/SiOx and SiOx/Si. Acting as the tunnelling oxide, this interlayer consists of trap states which are intrinsic in origin. The investigation on MOS structures fabricated using n and p type silicon substrates gives an understanding towards amphoteric nature of the trap states. Their nature (acceptor/donor) depends on the substrate doping type (n-Si/p-Si) giving it bipolar characteristic. However, the interaction of such trap states with the majority carrier band edge of the substrate strongly depends on the IL thickness. Additionally, the trap charge density increases with metal pulsing duration, suggesting that the metal precursor may be the source of these trap charges rather than the oxidant. By shedding light on the nature and behaviour of trap states in HfOx films, our study contributes to a deeper understanding of their impact on device performance. This knowledge can aid in optimizing surface passivation strategies and improving the overall performance of HfOx-based devices in various applications.

Electrical Properties of Silicon Oxide Layers Subjected to High-Temperature Treatment Reproducing the Growth Conditions for Thin Carbon Films

Electrical Properties of Silicon Oxide Layers Subjected to High-Temperature Treatment Reproducing the Growth Conditions for Thin Carbon Films

Growth of Zn1−xNixO Thin Films and Their Structural, Optical and Magneto-Optical Properties

The radio frequency (RF) reactive sputtering technique has been used to prepare Zn1−xNixO thin films with 0 ≤ x ≤ 0.08. Composite targets were obtained by mixing and pressing NiO and ZnO powders. Sapphire, quartz and glass were used as substrates. X-ray diffraction analysis of Ni-doped ZnO films indicates that all samples are crystalised in a hexagonal wurtzite structure with a preferred orientation along the (002) plane. Any secondary phase, corresponding to metallic nickel clusters or nickel oxides was not observed. High-resolution transmission electron microscopy (HR-TEM) image observed for Zn1−xNixO thin film shows a strong preferred orientation (texture) of crystalline columns in the direction perpendicular to the substrate surface. Different surface morphology was revealed in AFM images depending on the film composition and growth condition. Optical absorption spectra suggest the substitution of Zn2+ ions in the ZnO lattice by Ni2+ ions. The energy bandgap value was also found a complex dependence with an increase in Ni dopant concentration. In photoluminescence spectra, two main peaks were revealed, which are ascribed to near band gap emission and vacancy or defect states. Faraday rotation demonstrates its enhancement and growth of ferromagnetism with the increase in Ni content of Zn1−xNixO thin films at room temperature.

Insights on film growth conditions on a floating substrate during reactive Ar/O2 bipolar high power impulse magnetron sputter deposition

We report several effects found in reactive bipolar high-power impulse magnetron sputtering (abbreviated as bipolar HiPIMS or BPH) discharges at the substrate level. The role of the negative peak current and the positive pulse voltage, U, on the deposition flux at the electrically insulating substrate is discussed and the results are compared to conventional DC discharges. In particular, the normalized energy flux, ϕ n , delivered to the substrate is found higher under BPH conditions at U = +300 V ( eV·nm−3) as compared to the HiPIMS ( eV·nm−3) and DCMS ( eV·nm−3) regimes which is assumed to be provoked by an intensification of the positive ion bombardment. Accordingly, the mean energy and the count of positively charged metal and gaseous ions increase in line with U as measured by energy-resolved mass spectrometry. Contrariwise, our analysis has shown a significant decrease (≈20 %) of negative oxygen ion count under BPH conditions.

High-Throughput Electrosynthesis of Gradient Polypyrrole Film Using a Single-Electrode Electrochemical System

As an effective approach for materials synthesis, bipolar electrochemistry has been earning a renewed interest nowadays thanks to its unique features compared to conventional electrochemistry. Indeed, the wireless mode of electrode reactions and the generation of a gradient potential distribution above the bipolar electrode are among the most appealing qualities of bipolar electrochemistry. In particular, the gradient potential distribution is a highly attractive characteristic for the fabrication of surfaces with gradients in their chemical properties or molecular functionalities. Herein, we report the high-throughput electrosynthesis of gradient polypyrrole films by means of a new electrochemical cell design named the single-electrode electrochemical system (SEES). SEESs are made by attaching an inert plastic board with holes onto an indium tin oxide electrode, constructing multiple microelectrochemical cells on the same electrode. This type of arrangement enables parallel electrochemical reactions to be carried out simultaneously and controlled in a contactless manner by a single electrode. Several experimental conditions for polypyrrole film growth were extensively investigated. Furthermore, the gradient property of the polymer films was evaluated by thickness determination, surface morphology analysis, and contact angle measurements. The use of SEES has been demonstrated as a convenient and cost-effective strategy for high-throughput electrosynthesis and electroanalytical applications and has opened up a new door for gradient film preparation via a rapid condition screening process.

(Invited) Advances in Atomic Layer Processing of Hafnia-Zirconia Ferroelectrics

The limits of integrating ferroelectric materials on commercial semiconductor chips were demolished the moment ferroelectricity in hafnia and zirconia films was reported in 2011. This breakthrough moment in the history of ferroelectric materials was made possible by the fortuitous interplay between advances in atomic layer processing and the strong surface energy dependence of crystal phases in HfO2 and ZrO2. Aided by commercial investment in using both materials as high-k gate and DRAM dielectric materials, atomic layer deposition (ALD) processes are beginning to take full advantage of the completely solid-soluble hafnia-zirconia (Hf1-xZrxO2) ferroelectric system with new precursors and new insights obtained by systematically evaluating film growth conditions. The capability to precisely adjust the compositional profile and to alter oxidation conditions during atomic layer deposition film growth are giving an unprecedented level of control to engineer Hf1-xZrxO2 and doped HfO2 thin films for ferroelectric applications.The latest advances in atomic layer processing of Hf1-xZrxO2 and doped-HfO2 are presented where the dynamic interaction between composition and film growth conditions provide an engineering roadmap to adjust the physical and structural properties of the dielectric films. Metal precursors play a crucial role in the ensuing film properties. The adjustability of the electrical and structural properties of Hf1-xZrxO2 with ozone exposure during ALD film growth is discussed with respect to the important role oxygen and oxygen vacancies have in the overall phase stability of these novel ferroelectric materials, as well as C incorporation caused by ALD precursors. Just as atomic layer deposition has proven to be instrumental in the discovery and stabilization of the ferroelectric phase in HfO2-based thin films, atomic layer etching (ALE) of HfO2/ZrO2-based layers is now being used to preserve ferroelectricity while pushing the thickness dimension to new limits, yielding high performance films for ferroelectric tunnel junction applications. Further innovations in atomic layer processing will continue to be a harbinger of high performance ferroelectrics in the coming years based on the current status and future outlook for ferroelectric Hf1-xZrxO2 and other emerging ferroelectric materials.

Mapping the effect of substrate temperature inhomogeneity during microwave plasma-enhanced chemical vapour deposition nanocrystalline diamond growth

It is important to account for variance in substrate temperature during microwave plasma-enhanced chemical vapour deposition (MPECVD) nanocrystalline diamond growth, as this has a significant impact on the uniformity of the grown film. In this work, an in-situ method of mapping the substrate temperature under MPECVD growth conditions is demonstrated, employing a mirror galvanometer to scan the field of view of a dual-wavelength pyrometer across the substrate. Temperature maps generated were compared to plasma electron densities simulated using a finite element model. An increase in temperature and simulated plasma density were seen towards the centre of the holder. The properties of nanocrystalline diamond films were mapped using ex-situ Raman spectroscopy and spectroscopic ellipsometry (SE). A greater SE-measured bulk thickness and bulk sp3 fraction, as well as a greater first-order diamond Raman intensity and lower full width at half maximum were seen in the higher-temperature central region, demonstrating the impact of substrate temperature inhomogeneity during growth. The temperature mapping technique demonstrated allows easy evaluation of the impact of substrate holder design, microwave power and chamber pressure on substrate temperature homogeneity, and therefore optimisation of growth conditions for uniform diamond film growth.

Perpendicularly magnetized epitaxial Co/Ni multilayers grown on Ru(0001) layers by alternate monoatomic layer deposition

The hcp stacked Bh-ordered CoNi film was a candidate material to simultaneously have large uniaxial magnetic anisotropy energy (Ku) and a low Gilbert damping constant, which were previously predicted by a first-principles calculation. In this paper, we investigated the film growth condition to form the hcp stacked CoNi layers. [Co(1 ML)/Ni(1 ML)]N multilayers were epitaxially grown on Al2O3(11-20)/Ru(0001) underlayers by molecular beam epitaxy using an alternate monoatomic layer deposition technique with changing growth temperature (Ts) and repetition number (N). As the results of structural characterizations by x-ray diffraction measurements, it was found that the fcc- and hcp-CoNi phases were mixed in the samples, and the volume fraction of the fcc phase was larger than that of the hcp phase. However, the formation of the hcp-CoNi phase was promoted near the interface with the Ru layer having the hcp structure. The low growth temperature and the small N increased the volume fraction of the hcp phase. The Ku value of 5.1 Merg/cm3 was achieved for the [Co(1 ML)/Ni(1 ML)]20 multilayer grown at room temperature. In addition, a perpendicularly magnetized film was realized even for the thin sample with N = 5 (2 nm). This means that the Co/Ni multilayers are a thin ferromagnetic material suitable for application to spintronic devices.

Manipulated magnetic coercivity and spin reorientation transition in NiCo2O4 films

Half-metallic NiCo2O4 with high spin polarizability has great potential applications in spintronics. The manipulation of magnetic anisotropy is crucial for spintronics based on spin-transfer or spin–orbit torques, as it is directly related to the critical switching current density. Here, we report epitaxial growth of metallic NiCo2O4 film with perpendicular magnetic anisotropy on MgAl2O4 single crystal substrates. The modulation of the magnetic anisotropy was achieved by changing the growth conditions (deposition temperature and thickness) of NiCo2O4 films and by means of protonation. Strong dependence of magnetic coercivity on deposition temperature (350–500 °C) has been observed due to variable phase configuration. Furthermore, the magnetic coercive field can also be effectively controlled by the film thickness (3–78 nm) through strain relaxation. More importantly, spin reorientation transition has been achieved by proton and electron doping in the NiCo2O4 films, resulting in reconfigured valence states of Ni and Co cations and a magnetic easy axis rotation from out-of-plane to in-plane. The effective modulation of the magnetic anisotropy provides important insights into the functional design of NiCo2O4-based spintronics with ultralow energy dissipation.