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Analyses of orientational superlattice domains in epitaxial ZnTe thin films grown on graphene and mica
摘要： 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)110]ZnTe==[1(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)110]ZnTe==[100]mica (or [(1)110]ZnTe==[2(1)(1)10]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.
关键词： geometrical superlattice area mismatch model,mica,van der Waals epitaxy,X-ray pole figure,graphene,ZnTe,epitaxial growth
更新于2025-09-10 09:29:36
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Space-confined physical vapour deposition of high quality ZnTe nanosheets for optoelectronic application
摘要： Low-dimensional semiconductor nanomaterials with novel properties hold great promise for potential electronics and photonics applications. Here we report the growth of high quality ultra-thin ZnTe nanosheets by a space-confined physical vapour deposition route. The as-prepared ZnTe nanosheets are well crystallized and exhibit the zinc-blende crystal structure, with lateral dimension up to tens of micrometers and thickness thin to tens of nanometers. P-type conductivity was confirmed by field-effect transistors based on the individual nanosheet. Photodetectors constructed by the high-quality ZnTe nanosheets exhibit high photoresponsivity (453.9 A W?1), excellent stability and reliability. These results reveal that such high-quality ZnTe nanosheets are excellent candidates for optoelectronic applications.
关键词： Space-confined growth,Photodetectors,Electrical properties,Physical vapour deposition,ZnTe nanosheets
更新于2025-09-04 15:30:14