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 V 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 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 O 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 .