Enhanced Performance of Gallium-Based Wide Bandgap Oxide Semiconductor Heterojunction Photodetector for Solar-Blind Optical Communication via Oxygen Vacancy Electrical Activity Modulation

Gallium oxide (beta-Ga2O3) is a prominent representative of the new generation of wide-bandgap semiconductors, boasting a bandgap of approximate to 4.9 eV. However, the growth process of beta-Ga2O3 materials introduces unavoidable oxygen vacancies (Vo), leading to persistent photoconductivity (PPC), a phenomenon that severely hinders device performance. In this study, an innovative approach is successfully developed by introducing high p-orbital energy nitrogen (N). This leads to the formation of a hybridized state with O 2p orbitals in beta-Ga2O3, resulting in the creation of GaON and suppressing the electrical activity of Vo. Through meticulous experimentation and advanced computational methods, a comprehensive and insightful explanation of the regulation and mechanism underlying this passivation process is offered. Moreover, pn-junction solar-blind photodetectors are engineered using hybridized GaON thin films with p-type CuPc. These photodetectors demonstrate exceptional characteristics, including ultra-low dark current (10-14 A), high photo-to-dark current ratio (106), and rapid decay speed (0.008 s) even at zero bias. Based on these advancements, a solar-blind ultraviolet communication system is designed, featuring straightforward and reliable encoding, easy implementation, and robust anti-interference capabilities. By utilizing the N 2p-O 2p orbital hybridization, the valence band electron energy band structure is effectively modulated, suppressing the electrical activity of oxygen vacancies and sustaining the photoconductive effect.image