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SnTe is receiving a lot of attention as a topological crystalline insulator. Herein, SnTe films are grown directly on GaAs (100) substrates by molecular beam epitaxy. The surface morphology and electronic properties are measured by atomic force microscopy and Hall effect measurement, respectively. Considering previous X‐ray diffraction results, the samples grown with high beam‐intensity ratios show hexagonal Te segregation in the films, which deteriorates the surface morphology and decreases the conductivity. By suppressing the supply of Te, better surface morphology and electrical properties are obtained. [ABSTRACT FROM AUTHOR]

Discusses a study which described the growth of ZnSe thin films on silicon substrates by molecular beam epitaxy and reported the growth conditions and characteristics of the grown films. Techniques used in the evaluation of the epitaxial layers; Areas in which the thin films are applied; Overview of sample preparation.

Presents a study which examined the interdiffusion in ZnSe-ZnTe strained-layer superlattices grown by molecular-beam epitaxy. X-ray diffraction measurements of the superlattices; Experimental technique; Results and discussion; Conclusions.

Molecular beam epitaxy was used to fabricate Ag(In,Ga)Se2 (AIGS) thin films. To improve the diffusion of Ag, high-temperature deposition and high-temperature annealing methods were applied to fabricate AIGS films. The as-grown AIGS thin films were then used to make AIGS solar cells. We found that grain size and crystallinity of AIGS films were considerably improved by increasing the deposition and annealing temperature. For high-temperature deposition, temperatures over 600 °C led to decomposition of the AIGS film, desorption of In, and deterioration of its crystallinity. The most appropriate deposition temperature was 590 °C and a solar cell with a power conversion efficiency of 4.1% was obtained. High-temperature annealing of the AIGS thin films showed improved crystallinity as annealing temperature was increased and film decomposition and In desorption were prevented. A solar cell based on this film showed the highest conversion efficiency of 6.4% when annealed at 600 °C. When the annealing temperature was further increased to 610 °C, the performance of the cell deteriorated due to loss of the out-of-plane Ga gradient. [ABSTRACT FROM AUTHOR]

ZnTe/sapphire heterostructures have attracted attention for their suitable properties as a terahertz wave detector material. In this study, we focused on the selective growth of ZnTe on SiO2-masked sapphire substrates by molecular beam epitaxy (MBE). When ZnTe was grown at a high temperature (=350 °C), low growth rate (≦ 0.3 μm h−1), and low JTe/ JZn flux ratio (≦ 0.83) compared with the conventional film growth conditions, the formation of ZnTe nuclei on the SiO2 mask was avoided. The Te flux intensity significantly affected the selectivity of ZnTe growth. The selective growth of ZnTe on sapphire was revealed to be limited by the desorption of Te adatoms from the SiO2. [ABSTRACT FROM AUTHOR]

ZnTe epilayers were grown on R -plane ( $ 10 \bar 1 4 $) and S -plane ( $ 10 \bar 1 1 $) sapphire substrates by molecular beam epitaxy, and the crystal orientation and the optical property were studied. The crystal orientation of ZnTe layers on sapphire substrates was studied using X-ray diffraction pole figure measurements. It was confirmed that (111)-oriented domains were formed on the R -plane as well as on the S -plane substrate. Layers grown on R -plane exhibited higher film quality. From the low-temperature photoluminescence, emissions caused by ZnTe exciton were observed. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

ZnMgTe/ZnTe waveguide is a high potential electro-optical device. Thick and high Mg composition cladding layers are required for high optical performance waveguides. However, adding Mg would increase the lattice mismatch between ZnMgTe and ZnTe which would cause dislocation defects and generate asperities at interfaces. In this article, influence of the lattice mismatch strain to the waveguide surface morphology was studied. Waveguide structures were prepared by molecular beam epitaxy. The surface morphologies were observed using atomic force microscope and propagation loss of the waveguides were studied. Total of 0.5-0.7 μm asperities were observed on the surface of waveguides with 20% of Mg composition and 1.2 μm of the total cladding layer thickness. The asperities on the surface became larger (1.0-1.2 μm) when the Mg composition increased to 40%. The propagation loss of the waveguide was suppressed to 7 dB by tuning the growth parameters and the resulting interface roughness. [ABSTRACT FROM AUTHOR]

ZnTe epilayers were grown on transparent (10-10) oriented ( m -plane) sapphire substrates by molecular beam epitaxy (MBE). Pole figure imaging was used to study the domain distribution within the layer. (211)-oriented ZnTe domains were formed on m -plane sapphire. The presence of only one kind of (211) ZnTe domain formed on the 2°-tilted m -plane sapphire substrates was confirmed. Thus, single domain (211) ZnTe epilayers can be grown on the m -plane sapphire using MBE. Although differences in the crystal structure and lattice mismatch are large, precise control of the substrate surface lattice arrangement result in the formation of high-quality epitaxial layers. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Single-crystalline and single domain ZnTe thin films are sought for high-performance terahertz wave detectors, and ZnTe/sapphire heterostructures were considered since the Electro-Optical (EO) effect could be obtained only from epilayers. ZnTe epilayers were grown on m-plane sapphire substrates by molecular beam epitaxy, and the potential of single domain epilayers was explored. Through the X-ray diffraction pole figure measurement it was confirmed that one (100) oriented ZnTe domain along with two kinds of (211) oriented domains were formed on the m-plane sapphire when the layer was grown at 340 °C. When the layer was grown at 350 °C, the (211) oriented domain dominated the film. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The electro-optical effect of ZnTe is recently highlighted, and various device structures utilizing ZnTe are explored. ZnTe substrates are recently commercially available, and high quality homoepitaxial layers can be grown. On the other hand, the cost of the substrate could be a concern for the practical device application. In this study, Si and Al2O3 substrates were used since they are widely used for many kinds of device applications. The lattice mismatch between those substrate materials and ZnTe is above 10% and those mismatch strain should be carefully considered. ZnTe layers were nucleated on chemically treated substrate surfaces. (111), (110), (211) oriented Si substrates and (0001), (11-20), and (10-10) planes of Al2O3 were used. By taking the pole figure data and studying the crystal symmetry of the domain, detail information associated with the formation of domains in the layer was discussed. The pole figure analysis revealed that several kinds of (110) oriented ZnTe domains rotated 60 degrees each other were formed on (110) oriented Si surface. On the other hand, preferentially oriented single domain of (111) was confirmed for the layer grown on the (0001) plane of Al2O3. ZnTe layers grown on (10-10) plane Al2O3exhibited a unique domain formation. Pole figure data combined with the conventional theta-2theta measurement indicated that (211) oriented plane of ZnTe was a dominant domain formed on the (10-10) plane Al2O3. These crystallographic features would be related to the interface valency as well as the interfacial bond structure. X-ray pole figure method was a useful and powerful method to study the domain formation of the severely lattice mismatched structures. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

A ZnSe-ZnTe strained-layer superlattice (SLS) was grown on an InP substrate by molecular beam epitaxy for the first time. The x-ray diffraction measurement technique was used to confirm the existence of the high quality SLS structure. Overall quality may also be inferred from the observed quantum size effects of the photoluminescence data. [ABSTRACT FROM AUTHOR]

• The rock-salt structure SnTe thin films were grown on GaAs substrates by MBE. • SnTe (0 0 1) epilayers were confirmed from X-ray diffraction θ-2θ measurement. • Segregation of Te was also confirmed from samples grown with excess Te. • The molecular beam intensity ratio and growth temperature affected the orientation. • The substrate/epilayer interfacial region was observed by TEM. Tin–telluride (SnTe) thin films were grown on (0 0 1)-oriented GaAs substrates using molecular beam epitaxy. Samples were grown with various molecular beam intensity ratios at substrate temperatures of 225 °C and 240 °C. The crystallinity of the SnTe thin films was studied using X-ray diffraction θ –2 θ measurements. Stoichiometric SnTe layers were achieved by tuning both molecular beam intensity ratio and substrate temperature. It was also found that the excess Te remained in films when the molecular beam intensity ratio was Te rich. The (1 1 1)-oriented domain was confirmed when the substrate temperature was 240 °C. Continuous film formation was confirmed from cross-sectional transmission electron microscopy (TEM) observation. The segregation of Te for certain samples were also confirmed from the TEM energy dispersive x-ray mapping. [ABSTRACT FROM AUTHOR]

• Sapphire r,S-plane nanofaceted substrate was effective for growing ZnTe (1 1 0) thin film. • Zn irradiation during annealing suppressed the desorption of nuclei. • By improving the annealing and the MEE layer, ZnTe (1 1 0) crystallinity was improved. • An exciton-related feature was clearly observed from the PL measurement. ZnTe thin films were prepared on r, S-plane nanofacet substrates to achieve a high-crystal-quality layer with a (1 1 0) orientation. Scanning electron microscopy was used to study the nucleation process. Selective formation of growth nuclei can be achieved by controlling the substrate temperature. The low-temperature grown amorphous layers changed to nuclei by annealing. The surface amorphous layer was completely removed when the annealing temperature was too high. Zn beam irradiation during the annealing removed materials selectively from the r-nanofacet. Migration-enhanced epitaxy (MEE) was introduced to enlarge the nuclei size, and a thick-layer growth by conventional molecular beam epitaxy (MBE) followed. The MEE sequence was increased up to 1200 cycles, and the substrate temperature for MEE and MBE was set to higher temperatures than the conventional MBE substrate temperature (the conventional substrate temperature was around 340 °C). The crystal quality of the thin film was analyzed using the X-ray pole figure, θ–2θ measurements and photoluminescence. (1 1 0) oriented layer formation perpendicular to the substrate surface was confirmed after introducing those techniques. The low-temperature photoluminescence measurement indicated the high quality of the thick layer. [ABSTRACT FROM AUTHOR]