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ZnTe has a favorable band alignment with CdTe and is an ideal buffer between CdTe and metal contacts used in photovoltaics. Using metalorganic chemical vapor deposition, we report epitaxial growth of ZnTe thin films on 2D substrates, namely, single crystal graphene on amorphous SiO2/Si and freshly cleaved mica(001). Despite the large in-plane lattice mismatches between ZnTe and graphene (∼75%) and between ZnTe and mica(001) (∼17%), X-ray pole figure analyses show preferred epitaxial alignments with the out-of-plane orientation along [111] for ZnTe films on both substrates. For ZnTe on graphene, besides the primary in-plane orientation of [ 1 ¯ 10 ] ZnTe / / [ 1 1 ¯ ] graphene , two secondary in-plane orientations rotating ±25.28° away from the primary domain are found. A geometrical superlattice area mismatch (GSAM) model is implemented to explain the existence of the primary and secondary domains in ZnTe on graphene. For ZnTe on mica(001), only one in-plane orientational domain is found experimentally with the epitaxial relationship of [ 1 ¯ 10 ] ZnTe / / [ 100 ] mica (or [ 1 ¯ 10 ] ZnTe / / [ 2 1 ¯ 1 ¯ 0 ] mica if four-index notation is used for mica). However, the prediction of domain orientation between ZnTe and mica(001) based on the GSAM model slightly deviates from that observed experimentally. Furthermore, it should be noted that multiple order twinning domains of the primary domain are observed in both ZnTe films. While coexisting with the primary domain, each of the twinning domains is still epitaxially aligned with respect to the substrate. The in-depth understanding of ZnTe's epitaxial behaviors on graphene and mica(001) provides a valuable guidance for future studies on epitaxy of 3D zinc-blende overlayers on 2D hexagonal substrates. [ABSTRACT FROM AUTHOR]

Improvements in thermophotovoltaic devices can be achieved through longer minority carrier diffusion lengths, which fosters optical absorption in the p-layer. Reduced dependency on the influence of surface passivation can be achieved through thin emitter/thick base, n/p devices.

Epitaxial growth of n-type SiC was carried out using PH[sub 3] and N[sub 2] as the dopant precursors in a chemical vapor deposition system. Thermodynamic simulations were performed to analyze the gas phase composition at the growth conditions. It was shown that the incorporation behaviors of these two dopants are quite different. Compared to nitrogen, phosphorous incorporation has a weaker dependence on flow rate and has a limited site competition effect. Also, phosphorus incorporation for a given precursor flow decreases with temperature while that of nitrogen increases. It was also observed that phosphorous incorporation increases with decreasing C/Si when the ratio is between 0.8 and 3, which suggests phosphorous might incorporate into C site when C/Si is low. Variable temperature Hall measurements were used to characterize the doped layers. Two donor levels at 82-83 and 105-114 meV for phosphorous in 6H-SiC, 50-52 meV, and 78-80 meV for phosphorous in 4H-SiC were resolved. These results were compared to those from ion-implanted samples. [ABSTRACT FROM AUTHOR]

A two-step process for synthesizing stable Cs2SnI6perovskite thin films is reported in this letter. The two-step process includes the co-evaporation of two precursors SnI2and CsI onto a glass substrate, followed by a post thermal annealing process in iodine vapor. Using this technique, pure Cs2SnI6perovskite thin films were successfully synthesized without any wet process. These perovskite thin films are found to be stable under ambient conditions. They also show an electron mobility up to 509 cm2 V−1 s−1, which is higher than the mobilities of films prepared by solution processes reported in the literature. IMPACT STATEMENT A novel two-step dry process to synthesize phase-pure, air-stable Cs2SnI6perovskite thin film with higher electron mobility than that of the films prepared by the solution process. [ABSTRACT FROM AUTHOR]

This paper reports on the use of 10B nano/microparticles in order to fill microstructures of deep trenches fabricated in n-type Si (110) bulk wafers for the development of solid-state thermal neutron detectors. The high aspect-ratio trenches were fabricated in the wafer by wet etching, with a trench width of 3.5 to 6 µm and a maximum depth of 120 µm. Boron was diffused at a temperature of ~1000 °C in order to convert the entirety of the delicate Si microstructures into a p+-n junction diode. The deep trenches of the diode were completely filled with 10B nanoparticles using a simple room-temperature process involving the pumping and venting of a vacuum chamber containing the etched wafer with 10B nanoparticles atop. The simple filling process was reproduced consistently, and the best 2.5 x 2.5 mm² device demonstrated an intrinsic thermal neutron (En <0.5 eV) detection efficiency of 32.2 ± 1.5% under a self-biased condition. This result is promising as it demonstrates a complete, low-cost fabrication process for the development of efficient thermal neutron detectors. [ABSTRACT FROM AUTHOR]