Baoshi Qiao

Insect-inspired polarization vision systems leverage incident light polarization as an additional dimension for weighting synaptic responses, enabling on-device discrimination of dynamic environmental stimuli and efficient visual information processing. However, existing polarization-sensitive vision devices often face limitations such as suboptimal performance, high power consumption, and poor CMOS compatibility. This work demonstrates a ReS₂/p⁺-Si polarization-sensitive synaptic junction field-effect phototransistor that utilizes the rich polarization information carried by light to perform visual preprocessing directly at the device level, thereby reducing computational burdens on downstream processors. The device exhibits energy-efficient transistor characteristics, including a field-effect mobility of 12.5 cm² V^–1 s^–1, a low subthreshold swing of 74 mV/dec, and a high on/off ratio of 10⁵. Furthermore, its polarization-tunable synaptic response facilitates polarization-dependent functionalities such as contrast enhancement, glare suppression, and fingerprint recognition, offering a path toward polarization-enhanced neuromorphic vision sensing.

Recently, heterojunctions consisting of hybrid organic-inorganic lead (Pb) halide perovskites and other semiconductors have drawn increasing attention for the potential application in photodetectors due to their exceptional performance. However, their performance is usually limited by the relatively low crystalline quality of perovskites, and the response spectra of the devices are difficult to adjust according to the practical requirement. Here, high quality CH₃NH₃PbCl₃ micro-sized crystals have been successfully fabricated on one side of individual ZnO microwire to form heterojunction photodetector by a two-step crystallization method. The heterojunction device presents a low dark current (60 nA at −6 V) along with a rapid response speed (rise time of μs and fall time of ∼500 μs). More interestingly, the modulation of the response spectra and the responsivity can be realized by operating the device under front or back illumination due to the self-filtering properties. Our findings provide a promising method for combining perovskites with other inorganic materials to form high-performance heterojunction photodetectors.

An ideal solar-blind photodetector should possess high responsivity, low dark current, high speed, high spectral selectivity, high stability and a facile fabrication method. In this work, a high-quality single β-Ga₂O₃ microbelt photodetector is fabricated through low-pressure chemical vapor deposition and in situ atmospheric pressure annealing techniques. Due to the high quality and low defect density, this device shows a peak responsivity of 9.47 A W⁻¹ at 256 nm, a dark current of 1 pA and an ultrashort fall time of 1.37 μs under 20 V bias. Moreover, an ultrahigh specific detectivity of ∼10¹⁴ Jones and an extremely large solar-blind/ultraviolet A rejection ratio of nearly 10⁵ have also been achieved, suggesting the excellent sensitivity and wavelength selectivity of our single β-Ga₂O₃ microbelt photodetector. Besides that, the β-Ga₂O₃ microbelt photodetector exhibits excellent mechanical and long-term stabilities. Our findings provide a facile and promising route to develop high performance solar-blind UV photodetectors.

Detectivity is the most key parameter in weak-signal photodetection, which depends on high photoresponse and low noise simultaneously. In this work, metal–semiconductor–metal solar-blind UV detectors with internal gain were fabricated based on high resistant and a certain oxygen vacancy density Ga ₂ O ₃ thin films. Electrical measurements and electric field simulation indicated that thickening the active layer is helpful for high responsivity. The gain is dominated by the tunneling effect in high electric field under the electrodes. A high photoresponse of 371 A/W and a normalized detectivity up to $6.6\times10$ ¹⁶ Jones were obtained.

The sensitivity to weak light signals is a key parameter for UV photodetectors. However, a highly sensitive device has to suffer slow response speed (with photoconductive gain) or large noise current (with avalanche gain). In this work, a new type of photoconductive gain with controllable response speed is discovered in the Ga₂O₃ photodetector. The persistent photocurrent can be quenched by a 500 μs zero-voltage pulse. The photoconductive gain and the quenching of persistent photocurrent are respectively attributed to the forming and breaking of conductive filaments composed of oxygen vacancies. UV illumination has been demonstrated to accelerate the formation of the filament. This work provides a direction for the combination of speed-control and high sensitivity for photodiodes.