RESUMO
Integrating two-dimensional (2D) layered materials with wide bandgap ß-Ga2O3 has unveiled impressive opportunities for exploring novel physics and device concepts. This study presents the epitaxial growth of 2D ß-In2Se3/3D ß-Ga2O3 heterostructures on c-Sapphire substrates by plasma-assisted molecular beam epitaxy. Firstly, we employed a temperature-dependent two-step growth process to deposit Ga2O3 and obtained a phase-pure ( 2 ¯ 01 ) ß-Ga2O3 film on c-Sapphire. Interestingly, the in-situ reflective high-energy electron diffraction (RHEED) patterns observed from this heterostructure revealed the in-plane 'b' lattice constant of ß-Ga2O3 ~ 3.038Å. In the next stage, for the first time, 2D In2Se3 layers were epitaxially realized on 3D ß-Ga2O3 under varying substrate temperatures (Tsub) and Se/In flux ratios (RVI/III). The deposited layers exhibited (00l) oriented ß-In2Se3 on ( 2 ¯ 01 ) ß-Ga2O3/c-Sapphire with the epitaxial relationship of [ 11 2 ¯ 0 ] ß-In2Se3 || [010] ß-Ga2O3 and [ 10 1 ¯ 0 ] ß-In2Se3 || [102] ß-Ga2O3 as observed from the RHEED patterns. Also, the in-plane 'a' lattice constant of ß-In2Se3 was determined to be ~ 4.027Å. The single-phase ß-In2Se3 layers with improved structural and surface quality were achieved at a Tsub ~ 280 °C and RVI/III ~ 18. The microstructural and detailed elemental analysis further confirmed the epitaxy of 2D layered ß-In2Se3 on 3D ß-Ga2O3, a consequence of the quasi-van der Waals epitaxy. Furthermore, the ß-Ga2O3 with an optical bandgap (Eg) of ~ 5.04 eV (deep ultraviolet) when integrated with 2D ß-In2Se3, Eg ~ 1.43eV (near infra-red) can reveal potential applications in the optoelectronic field.
