Study on molybdenum disulfide layer growth on gallium nitride surface for high efficiency UV-visible photodetector

在这项研究中，我们计划开发用于短波长光电探测器的二硫化钼(MoS_2)和氮化镓(GaN)异质结。在这方面，我们研究了用化学气相沉积(CVD)方法在GaN表面上范德华异质外延生长MoS_2薄膜。以四硫代钼酸铵为前驱体，采用化学气相沉积技术在GaN衬底上合成了MoS_2三角晶体。用化学气相沉积方法在GaN衬底表面生长出了取向相同的三角形晶体。相同取向的三角形晶体的生长是由于MoS_2层与GaN之间较少的晶格失配。此外，用X射线光电子能谱研究了合成的MoS_2晶体与GaN晶片的界面质量。用合成的MoS_2层在GaN上制备了异质结器件，该器件具有良好的整流二极管特性和光伏效应。这项研究揭示了含氨的ATM前驱体在CVD工艺中在GaN上生长MoS_2晶体的适宜性，以获得适合器件应用的异质结构。同样，考虑到MoS_2层的催化活性，所开发的异质结构对于应用于制氢具有重要意义。

In this research, we proposed to develop molybdenum disulfide (MoS2) and gallium nitride (GaN) heterostructure for short wavelength photodetector applications. In this prospect, we have studied the van der Waal heteroepitaxial growth of MoS2 film by chemical vapor deposition (CVD) method on the GaN surface. Synthesis of MoS2 triangular crystals was achieved on Ga-terminated GaN substrate by the CVD technique using the ammonium tetrathiomolybdate precursor. Growth of triangular crystals on the GaN substrate surface with same orientation was obtained by the CVD process. The growth of triangular crystals with same orientation is due to less lattice mismatched between the MoS2 layer and GaN. Further, the interface quality of the as-synthesized MoS2 crystals and GaN wafer is explored by X-ray photoelectron spectroscopy. A heterojunction device is fabricated with the synthesized MoS2 layer on GaN, showing excellent rectifying diode characteristics and a photovoltaic action with light illumination. This study reveals the suitability of the ammonia-containing ATM precursor for the growth of MoS2 crystals on GaN in the CVD process to obtain a suitable heterostructure for device applications. Again, the developed heterostructure can be significant for application in hydrogen generation considering the catalytic activities of MoS2 layers.