Enhanced Photogain and Carrier Mobility via Modulating Exciton Generation and Transport of Amorphous-Alpha-Mixed Ga ₂ O ₃ Photodetector

Amorphous oxide semiconductors are one kind of fundamental material used in a wide range of devices and systems. Owing to recent hot research enthusiasm on wide bandgap semiconductors, amorphous Ga2O3 (a-Ga2O3) is attracting great interest especially for optoelectronics, but it is limited by low mobility for device applications. Therefore, toward high-performance operation, tuning the material properties becomes necessary. In this work, by modulating the in-furnace pressure in mist chemical vapor deposition (mist CVD), amorphous-α-mixed Ga2O3 (a-α-mixed Ga2O3) and a-Ga2O3 films were deposited on sapphire substrates. Ultraviolet photoresponse characteristics of both films were investigated based on a typical metal–semiconductor–metal photodetector (MSM PD) structure. Compared with a-Ga2O3, a-α-mixed Ga2O3 film shares higher responsivity (R) of 118 A/W, external quantum efficiency (EQE) of 57,969%, and specific detectivity (D*) of 2.82 × 1014 Jones. The enhanced photoresponse performance results from the improvement of carrier mobility, since the scattering is eliminated in the crystalline region for a-α-mixed Ga2O3 film. In all, the presented results provided a potential solution for low mobility in a-Ga2O3, guaranteeing its future application in a wide range of electronic/optoelectronic devices and systems.