Plasmon-Enhanced Performance in Self-Powered Solar-Blind CuCrO₂/<i>β</i>-Ga₂O₃ Heterojunction Photodetectors With Al Nanoparticles

<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-based heterojunction photodetectors (PDs) generally suffer from unsatisfactory low responsivity and low external quantum efficiency (EQE) due to the carrier blocking from imperfect band alignment. Herein, we demonstrate for the first time the significantly improved performance of self-powered solar-blind CuCrO2/<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 PDs by innovatively introducing Al nanoparticles (NPs) prepared by a facile electron beam evaporation technology with the subsequent high-temperature annealing technique. Compared with the conventional CuCrO2/<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 PD, the responsivity, detectivity, and EQE of the CuCrO2/<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 PD with Al NPs increase by 28.9, 39, and 28.9 times, respectively. In particular, our CuCrO2/<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 PDs show a low dark current of 3.67 pA, a high responsivity of 0.82 A/W, a high detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.09\times 10^{{13}}$ </tex-math></inline-formula> Jones, and a high EQE of 402.8%, which outperform most reported <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-based heterojunction PDs. Such brilliant performances can be attributed to the Al NPs, which improve the efficiency of hole injection and accelerate the generation rate and separation speed of photogenerated carriers via the combined effect of the localized electric field and the localized surface plasmon resonance (LSPR). These results show that the CuCrO2/<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 PD with Al NPs could achieve superior solar-blind sensitivity, thus providing a simple and feasible method to achieve high-performance ultraviolet PDs.