Transparent electronics has attracted much attention and been widely studied for next-generation high-performance flat-panel display application in the past few years, because of its excellent electrical properties. In display application, thin film transistors (TFTs) play an important role as the basic units by controlling the pixels. Among them, oxide-based TFTs have become promising candidates and gradually replaced the conventional amorphous and polycrystalline silicon TFTs, due to high mobility, good transparency, excellent uniformity and low processing temperature. Even though n-type oxide TFTs have shown high device performance and been used in commercial display application, p-type oxide TFTs with the equal performance have been rarely reported. Hence, in this paper, recent progress and challenges in p-type oxide-based TFTs are reviewed. After a short introduction, the TFT device structure and operation are presented. Then, recent developments in p-type oxide TFTs are discussed in detail, with the emphasis on the potential p-type oxide candidates as copper oxide, tin oxide and nickel oxide. Moreover, miscellaneous applications of p-type oxide TFTs are also presented. Despite this, the performance of p-type oxide TFTs still lags behind, as compared with that of n-type counterparts. Thus, the current issues and challenges of p-type oxide TFTs are briefly discussed.

Excellent device-to-device distribution was achieved in high-performance Ni/GeOx/TiOy/TaN resistive random access memory on low-cost flexible plastics, with low 30-μW switching power (9 μA at 3 V; - 1μA at -3 V), 10⁵ cycling endurance, and good retention at 85^°C. These were ascribed to bulk transport property by tunneling between traps, forming-free resistive switching, and the less destructive low power switching.

An optically pumped AlGaN-based vertical-cavity surface-emitting laser (VCSEL) in the deep ultraviolet (DUV) range (<; 280 nm) is demonstrated. The lasing wavelength is 275.91 nm with a threshold power density of 1.21 MW/cm ² and a linewidth of 0.78 nm. The lasing is believed to be benefited from high internal quantum efficiency (IQE) of the AlGaN-based multiple quantum wells (MQWs) and improved fabrication processes.

Thermal characteristics of GaN-based vertical cavity surface emitting lasers (VCSELs) with three typical structures were investigated both theoretically and experimentally. The simulation results based on a steady state quasi three-dimensional cylindrical model show that the thermal resistance ( R _th ) is affected by cavity length, mesa size, as well as the bottom distributed Bragg reflector (DBR) size, and the detail further depends on different structures. Among different devices, GaN VCSEL with a hybrid cavity formed by one nitride bottom DBR and another dielectric top DBR is featured with lower R _th , which is meanwhile affected strongly by the materials of the epitaxial bottom DBR. The main issues affecting the thermal dissipation in VCSELs with double dielectric DBRs are the bottom dielectric DBR and the dielectric current-confinement layer. To validate the simulation results, GaN-based VCSEL bonded on a copper plate was fabricated. R _th of this device was measured and the results agreed well with the simulation. This work provides a better understanding of the thermal characteristics of GaN-based VCSELs and is useful in optimizing the structure design and improving the device performance.

This letter reports on a tin oxide (SnO) thin-film transistor (TFT) with p-type conduction that uses aluminum (Al) doping in the SnO active channel layer. Performance enhancements were further achieved by applying fluorine plasma treatment on the p-type Al-doped SnO channel layer. The effects of the fluorine plasma treatment were also investigated.By tuning the power of the fluorine plasma treatment on the p-type Al-doped SnO channel layer, the optimal TFT device showed a very high on/off current ratio of 2.58×10⁶ and a low threshold swing of 174 mV/decade, which could be attributed to the passivation effect of the plasma fluorination on the dominant donor-like traps at the SnO/HfO₂ interface, as reflected by the suppression of the hysteresis phenomenon, the low density of interface traps, and the small subthreshold swing. The results indicate that the p-type Al-doped SnO TFT device with fluorine plasma treatment has considerable potential for application in future high-performance displays.