High performance solar-blind photodetectors based on plasma-enhanced atomic layer deposition of thin Ga2O3 films annealed under different atmosphere

Abstract

Solar-blind photodetectors (SBPDs) have attracted great interests for potential applications such as missile guidance, biological detection, and ultra-violet imaging. Although a large number of Ga2O3-SBPDs have been reported, most of them with thick light absorption layers still cannot effectively alleviate the trade-off between high responsivity and fast response time simultaneously. In this work, the high-performance Ga2O3 SBPDs with 20 nm ultra-thin film were fabricated. After annealing in nitrogen ambient at 900 ℃, the Ga2O3 SBPD demonstrated with a low dark current of 0.76 pA, a great photo-dark current ratio of 106, a high responsivity of 6.18 A/W, and an ultra-fast decay time of ∼45 ms. Moreover, the Ga2O3 films annealed in nitrogen exhibited a more pronounced amorphous-to-polycrystalline transition, while the samples showed a lower recrystallization and less oxygen vacancy concentration after oxygen annealing. This work provides a desirable strategy for developing high-performance SBPDs