The review explores CuInP ₂ S ₆ , a promising 2D van der Waals material with remarkable ferroelectric properties and potential applications in neuromorphic computing and memory devices, summarizing its properties, device designs, and future challenges.

In this work, a modified solution technique for synthesizing Ga ₂ O ₃ films is presented, which aims at fabricate high performance deep-ultraviolet (DUV) photovoltaic photodetectors (PDs). Through a selection of low boiling point organic solvent and high temperature heat treatment at 800 °C, the growth process of the films is optimized, with the single-crystal-oriented Ga ₂ O ₃ films synthesized on GaN substrate. A Pt/Ga ₂ O ₃ /GaN photodetector based on the film is fabricated, which exhibits a high photoresponsivity of 11.05 mA/W and a short decay time less than 48 ms under DUV irradiation and 0 V bias. Furthermore, tests on multiple devices fabricated by the same method at 0 V bias show a smallest ratio of 9.29% referring to the standard deviation of photocurrent to the average of the photocurrent (the ratio is defined as the coefficient of variation). It indicates that the improved solution technology for synthesizing Ga ₂ O ₃ films for the DUV photovoltaic PDs is reliable and reproducible. This research can serve as a reference for fabricating DUV photovoltaic PDs with high-performance based on solution-processed Ga ₂ O ₃ films.

2D van der Waals heterostructures offer great promise for memristors and neuromorphic computing. This review covers their preparation methods, band structures, switching mechanisms in memristors, and neuromorphic computing applications.

This work proposes a strategy of alloying SnO _x with Lu ₂ O ₃ to form an ultra-wide bandgap (>4.5 eV) ternary alloy film based on which a high-performance deep ultraviolet (DUV) detector is fabricated. A series of Lu _y Sn _1-y O _x (0 ≤ y ≤ 0.24) amorphous films are deposited on SiC substrates by magnetron sputtering with their band gap continuously adjustable from 4.0 eV to 4.9 eV. The findings here both confirm the feasibility of widening the band gap of Lu-alloyed SnO _x by increasing Lu content for the first time and prove the potential owned by this wide-bandgap alloy film in the field of DUV detection. This work can provide a reference for developing DUV detection technology through bandgap engineering in the future.

In this article, a simple and reproducible technology combining one-step thermal oxidation and the spraying method is presented for fabricating the high-performance organic-inorganic hybrid solar-blind ultraviolet (SBUV) photodetector (PD). $\beta $ -Ga2O3/GaN het- erojunction is readily built by the one-step thermal oxidation and sprayed with organic transparent conductive PEDOT:PSS to finish the construction of PEDOT:PSS/ $\beta $ -Ga2O3/GaN organic-inorganic hybrid heterojunction devices. Here, the optimal dosage of PEDOT:PSS is determined as 2 mL by balancing its SBUV transmittance and conductivity. The optimized device constructed with this 2 mL PEDOT:PSS exhibits a high photoresponsivity of 8.52 mA/W, a fast response with a decay time of 40.7 ms, and an SBUV-UV injection ratio ( ${R}_{\text {258 nm/365 nm}}$ ) over three orders of magnitude under 0 V bias and SBUV light irradiation. In addition, the feasibility of using PEDOT:PSS/ $\beta $ -Ga2O3/GaN SBUV PD as an optical receiver for secure SBUV communication systems encrypted by international Morse code has been verified. The low-cost and high-efficiency synthesis of gallium oxide as well as the preparation of organic-inorganic hybrid SBUV PDs proposed in this study can provide a new reference for the large-scale production of $\beta $ -Ga2O3-based high-performance heterojunction SBUV photovoltaic (PV) PDs.

In this work, a low-temperature solution process is proposed to synthesize Lu ₂ O ₃ films with few surface defects for the purpose of fabricating high-performance deep-ultraviolet (DUV) detectors. Based on the solution-processed Lu ₂ O ₃ film treated at 250 °C, a high-sensitivity Lu ₂ O ₃ /GaN DUV photovoltaic detector is fabricated, which has exhibited excellent performance in many aspects. At 0 V bias voltage, it displays a peak photoresponsivity of 41.6 mA/W at 258 nm and a DUV to visible rejection ratio ( $\text{R}_{258\,\text{nm}} / \text{R}_{405\,\text{nm}}$ ) higher than two orders of magnitude. What’s more, compared with devices based on high-temperature (500 °C) solution-processed (H-T) Lu ₂ O ₃ film, the device prepared in this way shows a greater photoresponsivity and a response speed faster than an order of magnitude, which can be attributed to the fewer surface defects aroused during the low-temperature solution process. The great characteristics achieved suggest the Lu ₂ O ₃ film treated by the method of low-temperature solution process can be applied to fabricating high-performance DUV detectors.