For the frequency range of 1 kHz–10 MHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage (C–V) and conductance-frequency-voltage (G–f–V) measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance () on high-frequency (5 MHz) capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the – capacitance and the conductance method are and , respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.

Au/Ni/n-type 4H-SiC Schottky alpha particle detectors are fabricated and annealed at temperatures between 400 • C and 700 • C to investigate the effects of thermal stability of the Schottky contact on the structural and electrical properties of the detectors. At the annealing temperature of 500 • C, the two nickel silicides (i.e., Ni 31 Si 12 and Ni 2 Si) are formed at the interface and result in the formation of an inhomogeneous Schottky barrier. By increasing the annealing temperature, the Ni 31 Si 12 transforms into the more stable Ni 2 Si. The structural evolution of the Schottky contact directly affects the electrical properties and alpha particle energy resolutions of the detectors. A better energy resolution of 2.60% is obtained for 5.48-MeV alpha particles with the detector after being annealed at 600 • C. As a result, the Au/Ni/n-type 4H-SiC Schottky detector shows a good performance after thermal treatment at temperatures up to 700 • C.

Nowadays, the superior detection performance of semiconductor neutron detectors is a challenging task. In this paper, we deal with a novel GaN micro-structured neutron detector (GaN-MSND) and compare three different methods such as the method of modulating the trench depth, the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region (W ). It is observed that the intensity of electric field can be modulated by scaling the trench depth. On the other hand, the electron blocking region is formed in the detector enveloped with a dielectric layer. Furthermore, the introducing of p-type inversion region produces new p/n junction, which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction. It can be realized that all these methods can considerably enhance the working voltage as well as W . Of them, the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8 µm when the carrier concentration of p-type inversion region is 10 17 cm −3 . Consequently, the value of W is observed to improve 200% for the designed GaN-MSND as compared with that without additional design. This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.

Ag-doped ZnO (ZnO:Ag) films are prepared on c-plane sapphire substrates by pulsed laser deposition at different substrate temperatures. The effect of substrate temperature on the ZnO:Ag film is studied in detail by EDX, XRD and Raman spectroscopy. The results reveal that raising the substrate temperature is beneficial for incorporating Ag into ZnO:Ag films in the range of our experimental temperatures and a number of Ag atoms incorporation into ZnO:Ag films may cause the (002) peak positions of the XRD spectra shift to a lower angle direction, but hardly affect the c-axis orientation of the films. The (002) peak shift ought to be due to the increase of lattice constant in the c-axis direction caused by the partial substitution of Zn2+ ions by Ag+ ions. In addition, a local vibrational mode (LVM) at 492 cm−1 induced by doping Ag occurred in the Raman spectra of all the ZnO:Ag films and its peak position hardly shifted with increasing substrate temperature. It means that the LVM can act as an indication of Ag incorporation into ZnO:Ag film.