Hydrogen-terminated diamond (H-diamond) metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on a polycrystalline diamond substrate. The device has a gate length of 2 μm and uses Al2O3 grown by atomic layer deposition at 300 °C as a gate dielectric and passivation layer. The Al2O3/H-diamond interfacial band configuration was investigated by X-ray photoelectron spectroscopy, and a large valence band offset (3.28 eV) that is very suitable for p-channel H-diamond FETs was observed. Meanwhile, the measured O/Al ratio hints that there are Oi or VAl defects in the Al2O3 dielectric, which can work as an acceptorlike transfer doping material on a H-diamond surface. The device delivers the maximum saturation drain current of over 200 mA/mm, which is the highest for 2-μm H-diamond MOSFETs with the gate dielectric or passivation layer grown at 300 °C or higher temperature. The ultrahigh on/off ratio of 1010 and ultralow gate leakage current of below 10−12 A have been achieved. The high device performance is ascribed to the ultrahigh carrier density, good interface characteristics, and device processes. In addition, the transient drain current response of the device can follow the gate voltage switching on/off pulse at a frequency from 100 kHz to 1 MHz, which indicates the potential of the H-diamond FETs in power switch applications.

We report the performance of a single crystal diamond radiation detector with gold films on hydrogen-terminated diamond as electrical contacts and oxygen-terminated diamond as surface isolation between electrodes. The origin-symmetric current-voltage characteristics showed excellent Ohmic contact behavior. An extremely low dark current value of 7.46 × 10−13 A/mm2 was measured at an electric field of 1 V/μm. The charge collection efficiency and energy resolution of this detector were 99.01% and 1.5% for holes, and 98.6% and 1.7% for electrons under irradiation with 241Am α-particles. Under 60Co γ-ray irradiation with a dose rate of 1.271 Gy/s, the gain factor, specific sensitivities, and signal-to-noise ratio were 49.46, 12.43 μC/Gy·mm3, and 1 × 106 at 200 V bias voltage (0.66 V/μm), respectively. A rise time of 347.4 ps of the response to a pico-second pulsed electron source was also measured. This research provides a possibility to improve the performance of the diamond radiation detector through diamond surface modification.

In this work, a simple and convenient interface modification by nanosized diamond (ND) was used in the carbon based all-inorganic CsPbIBr 2 planar perovskite solar cells (PSCs). Only by spin-coating ND particles on the crystallized perovskite without further treatment did all CsPbIBr 2 PSCs achieve an overall improvement in photovoltaic performance. The champion PCE of ND modified PSC reached 9.07%, 22% higher than the control device (7.46%), and remained at 86% of its original value after 50 days. Particularly, the device obtained a V OC beyond 1.30 V and FF over 60% at the same time, which is superior to most of the reported CsPbIBr 2 PSCs. The results of light absorption, PL spectra, TPC, TPV, and electrochemical analysis revealed that the superior device performance mainly came from the improved light absorption and reduced carrier recombination in PSCs. Therefore, the ND provides a facile strategy to enhance the performance of CsPbIBr 2 PSCs.

High-quality GaN film is grown on graphene with the underneath sputtered AlN modified layer using metal organic chemical vapor deposition. Due to the modulation effect of sputtered AlN on the surface potential and the chemical reactivity of graphene, the nucleation probability of GaN is significantly improved. The GaN epitaxial layer shows excellent crystal quality and surface morphology, and has very low threading dislocation density of 1.78 Â 10 8 cm À2 . Furthermore, the mechanism of threading dislocation suppression is revealed according to the transmission electron microscope results. The improved nucleation probability and enhanced lateral growth mode lead to the formation of short-range stacking faults in c-plane GaN, which block the propagation of threading dislocations along the growth direction. Moreover, the formation and evolution mechanism of the shortrange stacking faults are discussed. The results in this work not only offer a promising approach to propel the widespread application of GaN on graphene, but also provide a new idea for the regulation and suppression of defects in the growth of nitride semiconductors.

The impact of gamma irradiation on GaN quasi-vertical Schottky barrier diodes (SBDs) has been investigated for the first time. Compared with original GaN SBDs, the ideality factor decreases from 1.2 to 1.01–1.02 and the on/off ratio increases from 109 to 1012 for the irradiated GaN SBDs. The reduction of dynamic on-resistance from 0.67 mΩ · cm2 to 0.54 mΩ · cm2 was observed at the quiescent bias of  −100 V compared with the original SBDs. The temperature dependent current characteristics has revealed the existence of Schottky barrier inhomogeneities at the anode/GaN Schottky interface, and the level of barrier inhomogeneities can be effectively suppressed after gamma irradiation. Based on x-ray photoelectron spectroscopy, cathodoluminescence and x-ray diffraction results, the interface state density at the interface and the deep electron trap in the bulk GaN are reduced after gamma irradiation. The voltage dependent capacitance-frequency measurements further confirm that the interface trap states dominate the degraded characteristics of pre-irradiated devices and the trap time constant is estimated to be in the range of 5 μs to 50 μs.