Recently, the research group of Professor Long Shibing from the School of Microelectronics, University of Science and Technology of China and Professor Zhu Bowen from Westlake University have prepared high-performance flexible high temperature resistant Ga2O3 deep ultraviolet detector by inkjet printing. Combined with the high design of inkjet printing and the efficient conversion of the precursor aqueous solution during annealing, a structured Ga2O3 thin film array with a thickness of 15 nm was prepared (Figure A-B). XRD and other characterization results showed that the printed films were finally transformed into high-quality crystal β-Ga2O3(FIG. c).
The Ga2O3 detector printed on A rigid substrate shows excellent detection performance at 254 nm, including up to 106 light/dark current ratio, 1.3 A/W response time and 0.026 s response time. Ga2O3 detectors prepared on a flexible substrate (mica) not only have comparable optical detection performance with rigid devices, but also show stable and considerable deep ultraviolet detection performance in a variety of bending radii (plane /5/4.25/3.5 mm)(FIG. d), even after multiple bending cycles. The excellent mechanical toughness of the device is mainly attributed to the ultra-thin thickness of the printed Ga2O3 and the high crystal quality induced by high temperature annealing and its strong adhesion to the ultra-thin mica substrate.
Although the light/dark current ratio decreases with increasing temperature, it remains above 105 at 250 ℃ (FIG. e), setting a new high temperature (200 ℃ and above)Ga2O3 photodetector record. In addition, thanks to the high uniformity of all pixels, the printing method flexible Ga2O3 detector array (4×4) exhibits a high contrast imaging effect (Figure f).
This work provides a high-throughput and low-cost optimal strategy for the preparation of high-performance flexible high-temperature deep ultraviolet photoelectrodetectors for deep space exploration in extreme environments and wearable electronics applications. The paper is published online in Advanced Optical Materials.