Realization of cost-effective and high-performance solar-blind ultraviolet photodetectors based on amorphous Ga2O3 prepared at room temperature

The solar-blind photodetectors based on amorphous Ga2O3 (a-Ga2O3) are attractive in recent years due to their simple fabrication process and good compatibility with different substrates. Herein, the cost-effective and high-performance thin-film transistor (TFT) type solar-blind photodetector based on a-Ga2O3 was realized successfully at room temperature without post-annealing treatment. The a-Ga2O3 phototransistor showed excellent performance under weak ultraviolet (UV) light illumination (30 μW/cm2). In addition to the low dark current (Idark = 7.12 pA), the optimized a-Ga2O3 phototransistor showed a high response to ultraviolet light. The photo-to-dark current ratio (PDCR) reached up to 4.79 × 105 and the photoresponsivity (R) was 151.56 A/W. Meanwhile, the photo-detectivity (D∗) and external quantum efficiency (EQE) were 2.75 × 1015 Jones and 7.38 × 104%, respectively. After being treated with the polyethyleneimine ethoxylated (PEIE) electron-donating layer, the photocurrent of the PEIE/a-Ga2O3 based phototransistor increased so that R and EQE were enlarged up to 206.22 A/W and 1.004 × 105% respectively. Such a-Ga2O3 solar-blind photodetector provides the avenue to develop the inexpensive and high-performance Ga2O3-based solar-blind photodetector.