【Epitaxy Papers】Structural and interface band alignment investigations on epitaxial β-Ga₂O₃/α-GaCrO₃ type-II transparent heterojunction

      Researchers from the Raja Ramanna Centre for Advanced Technology have published a dissertation titled "Structural and interface band alignment investigations on epitaxial β-Ga₂O₃/α-GaCrO₃ type-II transparent heterojunction" in Journal of Applied Physics.

Abstract

      Herein, we investigate structural and electronic properties of β-Ga₂O₃ and p-type Ni-doped α-GaCrO₃ (α-GaCrO₃:Ni) heterostructure, focusing on its potential for charge separation and rectification mechanisms. Thin films are grown using the magnetron sputtering technique. Synchrotron-based high-resolution x-ray diffraction and high-resolution transmission electron microscopy reveals a sharp and high-quality interface between β-Ga₂O₃/α-GaCrO₃:Ni/Al₂O₃ epitaxial layers and also confirm single-crystal epitaxial growth of monoclinic (−201) β-Ga₂O₃ along the [0001] direction of α-GaCrO₃:Ni. Optical measurements confirm an average transmission of more than 70% for all thin film samples, showing their potential for transparent optoelectronic devices. Using synchrotron-based photoelectron spectroscopy, valence band offset and conduction band offset at β-Ga₂O₃/α-GaCrO₃:Ni interface are determined to be 2.44 ± 0.2 and 1.44 ± 0.2 eV, respectively, which confirms a type II (staggered gap) energy band alignment at the heterojunction. This type of band alignment is highly useful in a wide range of photovoltaic and optoelectronic devices where efficient charge separation, reduced recombination, and rectification of charge carriers play an important role, such as in solar cells, UV photodetectors, and many other optoelectronic devices.

DOI：

https://doi.org/10.1063/5.0284059