Epitaxial growth and interface band alignment studies of all oxide α-Cr2O3/β-Ga2O3 p-n heterojunction

Epitaxial growth of alpha-Cr2O3(p-type) on c-Al2O3 and beta-Ga2O3 (n-type) on alpha-Cr2O3(p-type) has been carried out to make an all oxide epitaxial n-type beta-Ga2O3/p-type alpha-Cr2O3 heterojunction using RF sputtering. A valence band offset of 3.38 +/- 0.2 eV at the heterojunction is determined using Kraut's method. From the bandgap measurements of alpha-Cr2O3 and beta-Ga2O3, the conduction band offset of 1.68 +/- 0.2 eV at the heterojunction is obtained. Thus, the band alignment at this heterojunction is found to be staggered (Type-II), which leads to the confinement of electrons and holes in the beta-Ga2O3 layer and alpha-Cr2O3 layer, respectively. Our results provide a pathway to design all oxide optoelectronic devices based on a p-n heterojunction consisting of n-type beta-Ga2O3 and p-type alpha-Cr2O3. Published under license by AIP Publishing.