Enhanced Performance of NiO/β-Ga₂O₃ Heterojunction Photodetector via Piranha Treatment and Its Application to Solar-Blind Communication

In this work, we demonstrated a high-performance NiO/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 heterojunction photodetector using piranha solution pretreatment technology. After treatment, the NiO/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 heterojunction exhibited an excellent electrical performance, including a higher on/off ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 10^{{7}}$ </tex-math></inline-formula>, a lower reverse current of 0.28 pA, and an improved ideal factor. Additionally, the solar-blind detection performance of treated sample was significantly enhanced, including a 2900% increase in photo-to-dark-current ratio (PDCR), a 140% increase in responsivity, and a 900% increase in detectivity. Notably, excellent rise time and decay time were observed to be 60 and 50 ms after treatment, demonstrating an impressive reduction of 97% and 98%, respectively. This fast response characteristic has a wide range of applications. Thus, we conducted an optical communication test based on an original solar-blind communication system. Data transmission was successfully achieved ten times with a short sampling time of 100 ms. These results illustrate the effectiveness of piranha solution pretreatment in elevating the performance of Ga2O3-based heterojunction photodetector.