Large-area vertically stacked MoTe₂/β-Ga₂O₃ p-n heterojunction realized by PVP/PVA assisted transfer

Beta phase gallium oxide (β-Ga₂O₃) has attracted wide attention due to its unique material property; however, the lack of p-type doping hinders its practical application. Here, we report a 2H-MoTe₂/β-Ga₂O₃ (2-01) vertical p-n heterojunction diode via chemical vapor deposition, which exhibited excellent rectification characteristics with a rectifying ratio of 10⁵, and an on-current density of up to 1 mA/cm². The depletion comes from strain-free interface of the 2H-MoTe₂ and β-Ga₂O₃ (2-01) by van der Waals force. The band offsets and the interface element distribution of the heterojunction were investigated by the X-ray photoelectron spectroscopy and transmission electron microscope. The valence and conduction band offsets between the 2H-MoTe₂ and β-Ga₂O₃ were consequently determined to be 0.16 eV and 3.56 eV, with a nested gap (type I) band alignment. Moreover, an abnormal build-in potential was observed in the 2H-MoTe₂/β-Ga₂O₃ p-n heterojunction diode which could be attributed to the formation of an interfacial layer of MoO_X. These observations in the 2H-MoTe₂/β-Ga₂O₃ heterojunction show the great potential in optoelectronic devices.