As a typical two-dimensional material, graphitic carbon nitride (g-CN) has attracted great interest because of its distinctive electronic, optical, and catalytic properties. However, the absence of a feasible route toward large-area and high-quality films hinders its development in optoelectronics. Herein, high-quality g-CN films have been grown on Si substrate via a vapor-phase transport-assisted condensation method. The g-CN/Si heterojunction shows an obvious response to ultraviolet–visible-near infrared photons with a responsivity of 133 A·W⁻¹, which is two orders of magnitude higher than the best value ever reported for g-CN photodetectors. A position-sensitive detector (PSD) has been developed using the lateral photovoltaic effect of the g-CN/Si heterojunction. The PSD shows a wide response spectrum ranging from 300 to 1,100 nm, and a position sensitivity and rise/decay time of 395 mV·mm⁻¹ and 3.1/50 μs, respectively. Moreover, the application of the g-CN/Si heterojunction photodetector in trajectory tracking and acoustic detection has been realized for the first time. This work unveils the potential of g-CN for large-area photodetectors, and prospects for their applications in trajectory tracking and acoustic detection.

Ga₂O₃ has been regarded as a promising material for solar-blind detection due to its ultrawide bandgap and low growth cost. Although semiconductor microwires (MWs) possess unique optical and electronic characteristics, the performances of photodetectors developed from Ga₂O₃ MWs are still less than satisfactory. Herein, we demonstrate high-performance solar-blind photodetectors based on Sn-doped Ga₂O₃ MWs, possessing a light/dark current ratio of 10⁷ and a responsivity of 2,409 A/W at 40 V. Moreover, a 1 × 10 solar-blind photodetector linear array is developed based on the Sn-doped Ga₂O₃ MWs via a patterned-electrodes method. And clear solar-blind images are obtained by using the photodetector array as the imaging unit of a solar-blind imaging system. The results provide a convenient way to construct high-performance solar-blind photodetector arrays based on Ga₂O₃ MWs, and thus may push forward their future applications.

Flexible photodetectors (PDs) are indispensable components for next-generation wearable electronics. Recently, two-dimensional (2D) materials have been implemented as functional flexible optoelectronic devices due to their characteristics of atomically thin layers, excellent flexibility, and strain sensitivity. In this work, we developed a flexible photodetector based on MoS₂/NiO heterojunction, and Fabry-Perot (F-P) and piezo-phototronic effect have been employed to enhance the responsivity (R) and external quantum efficiency (EQE) of the devices. The F-P effect is utilized to improve the optical absorption of the MoS₂, resulting in an enhancement in the photoluminescence (PL) of monolayer MoS₂ and the EQE of the photodetector by 30 and 130 times, respectively. The flexible photodetector exhibits an ultrahigh detectivity (D*) of 2.6 × 10¹⁴ Jones, which is the highest value ever reported for flexible MoS₂ PDs. The piezo-potential of monolayer MoS₂ decreases the valence band offset at the interface of MoS₂/NiO, which increases the transfer efficiency of the photon-generated carriers significantly. Under 1.17% tensile strain, the R of the flexible photodetector can be enhanced by 271%. This research may provide a universal strategy for the design and performance optimization of 2D materials heterostructures for flexible optoelectronics.

The quest for solar-blind photodetectors with outstanding optoelectronic properties and weak signals detection capability is essential for their applications in the field of imaging, communication, warning, etc. To date, Ga₂O₃ has demonstrated potential for high-performance solar-blind photodetectors. However, the performance usually decays superlinearly at low light intensities due to carrier-trapping effect, which limits the weak signal detection capability of Ga₂O₃ photodetectors. Herein, a Ga₂O₃ solar-blind photodetector with ultra-thin absorbing medium has been designed to restrain trapping of photo-generated carriers during the transporting process by shortening the carrier transport distance. Meanwhile, multiple-beam interference is employed to enhance the absorption efficiency of the Ga₂O₃ layer using an Al/Al₂O₃/Ga₂O₃ structure. Based on the ultra-thin absorbing medium with enhanced absorption efficiency, a 7 × 7 flexible photodetector array is developed, and the detectivity can reach 1.7 × 10¹⁵ Jones, which is among the best values ever reported for Ga₂O₃ photodetectors. Notably, the performance of the photodetector decays little as the illumination intensity is as weak as 5 nW/cm², revealing the capacity to detect ultra-weak signals. In addition, the flexible photodetector array can execute the functions of imaging, spatial distribution of light source intensity, real-time light trajectory detection, etc. Our results may provide a route to high-performance solar-blind photodetectors for ultra-weak light detection.