Gallium oxide (Ga₂O₃), an ultrawide bandgap semiconductor, is an ideal material for solar-blind photodetectors, but challenges such as low responsivity and response speed persist. In this paper, one-dimensional (1D) Ga₂O₃ nanorods were designed to achieve high photodetection performance due to their effective light absorption and light field confinement. Through modulating source concentration, pH value, temperature, and reaction time, 1D β-Ga₂O₃ nanorods were controllably fabricated using a cost-effective hydrothermal method, followed by post-annealing. The nanorods had a diameter of ~500 nm, length from 0.5 to 3 μm, and structure from nanorods to spindles, indicating that different β-Ga₂O₃ nanorods can be utilized controllably through tuning reaction parameters. The 1D β-Ga₂O₃ nanorods with a high length-to-diameter ratio were chosen to construct metal-semiconductor-metal type photodetectors. These devices exhibited a high responsivity of 8.0 × 10⁻⁴ A/W and detectivity of 4.58 × 10⁹ Jones under 254 nm light irradiation. The findings highlighted the potential of 1D Ga₂O₃ nanostructures for high-performance solar-blind ultraviolet photodetectors, paving the way for future integrable deep ultraviolet optoelectronic devices.

Utilizing 2D layered semiconductor as ultrafast photoacoustic transducer, we all-optically generate and track the propagation of picosecond acoustic pulses in 2D layered semiconductor/PMMA thin-film heterostructure via femtosecond laser pump-probe. By varying the environmental temperatures and the incident direction of pump laser pulse, the acoustic velocity of PMMA thin-film has been in situ monitored. The glass transition temperature of PMMA has been measured. Our work provides an all-optical means to noninvasively evaluate thermal responses of polymer thin-films, which are important for studies of thermal interface materials and thermal management of microelectronic devices.

Heterojunction is an alternative strategy to achieve pure ultraviolet electroluminescence (UV EL) in situation of p-type doping absence for ZnO homojunction. However, the most reported n-ZnO/p-GaN heterojunction device exhibited broad EL spectra, generally including blue emission from GaN, UV emission from ZnO, and blue-violet emission from ZnO/GaN interface. Herein, to realize pure UV EL of ZnO, one-dimensional ZnO/AlN core-shell structure was fabricated and then bonded with p-GaN to establish an n-ZnO/AlN/p-GaN heterojunction. In this device, the wide-bandgap AlN buffer was sputtered on the surface of the ZnO core as a shell layer, forming a suitable energy-band configuration with a high electron barrier to prevent electron injection from ZnO to GaN and a low valence band offset to keep hole injection from GaN to ZnO. Owing to the well-matched lattices of ZnO and AlN, a high-quality ZnO/AlN interface was established to block electrons more sufficiently. Meanwhile, the perfect ZnO/AlN core-shell structure resulted in the effective surface defect passivation, thus effectively improving the inter-band recombination of ZnO. After optimizing the AlN buffer width to 15.38 nm, the carriers recombination region was controlled significantly on the ZnO side, so that the heterojunction generated a pure UV EL, peaking at 382 nm with a narrow full width at half maximum of about 13 nm, which aligned perfectly with the photoluminescence of high quality ZnO.

Optoelectronic logic gates, with high-speed, low-power consumption, and broad bandwidth, have attracted significant attention in high-density information processing applications. It would be more attractive and challenging to carry out multifunctional logic operations in an individual device due to the inherent nature of unidirectional carrier transport. Herein, a transistor-like one-dimensional ZnO/CH3NH3PbBr3 heterostructure is designed for an all-optically controlled logic gate that exhibits wavelength- and power-dependent bipolar photoresponse. Under visible light illumination, the device presents a negative photoresponse, while a transformation from negative to positive photoresponse emerges with increasing ultraviolet irradiation power. Time-resolved photoluminescence spectra demonstrate the carrier dynamics involving defect trapping about the negative-positive photoconductive switching. Based on the bipolar photoresponse, five fundamental logic operations (OR, AND, NOR, NOT, and NAND) are implemented in an individual device, which substantially enhances integration density while reducing power consumption. This work presents an optical sensing-computing integrated architecture for the multifunctional optoelectronic chips and non-Von Neumann intelligent sensors.

Using an identical monolithic InGaN/GaN light emitting diode (LED) array as the sensing module and a well-designed data processing module, we demonstrate a small-size concentration sensing prototype. Overlap between the emission and the response spectra of the InGaN/GaN LED makes each pair of LEDs in the arrayed chip form a sensing channel. The changes in liquid concentration can be transformed into variation of photocurrent. The system’s sensing properties are further optimized by varying the position, number of receivers, and packaging reflectors. With methyl orange as a tracer agent, the sensing system’s resolution is 0.286 µmol/L with a linear measurement region below 40 µmol/L.