关键词: amorphous gallium oxide, magnetron sputtering, atomic layer deposition, ultraviolet detectors, dangling bonds

Abstract: Low-cost and large-area uniform amorphous Ga$_{2}$O$_{3}$ (a-Ga$_{2}$O$_{3}$) solar-blind ultraviolet (UV) detectors have garnered significant attention in recent years. Oxygen vacancy (V$_{\rm O}$) defects are generally considered as the predominant defects affecting the detector performance. Reducing V$_{\rm O}$ concentration generally results in both low dark current and low photo current, significantly limiting further improvement of the photo-to-dark current ratio (PDCR) parameter. Herein, a delicately optimized atomic layer deposition (ALD) method is revealed having the capability to break through the trade-off in a-Ga$_{2}$O$_{3}$, achieving both low dark current and high photocurrent simultaneously. For a clear demonstration, a-Ga$_{2}$O$_{3 }$ contrast sample is prepared by magnetron sputtering and compared as well. Combined tests are performed including x-ray photoelectron spectroscopy, photoluminescence, electron paramagnetic resonance and Fourier-transform infrared spectroscopy. It is found that ALD a-Ga$_{2}$O$_{3}$ has a lower V$_{\rm O}$ concentration, but also a lower dangling bonds concentration which are strong non-irradiation recombination centers. Therefore, decrease of dangling bonds is suggested to compensate for the low optical gain induced by low V$_{\rm O}$ concentration and promote the PDCR to $ \sim 2.06 \times 10^{6}$. Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga$_{2}$O$_{3}$ detection performance, offering new insights for further promotion of a-Ga$_{2}$O$_{3 }$ UV detector performance via dual optimization of dangling bonds and V$_{\rm O}$.

Key words: amorphous gallium oxide, magnetron sputtering, atomic layer deposition, ultraviolet detectors, dangling bonds