Unraveling the role of dangling bonds passivation in amorphous Ga2O3 for high-performance solar-blind UV detection

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 O ) defects are generally considered as the predominant defects affecting the detector performance. Reducing VO 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 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 VO concentration and promote the PDCR to ~2.06 × 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 O .