for a finite group G, we denote by p(G) the minimal degree of faithful permutation representations of G, and denote by c(G), the minimal degree of faithful representation of G by quasi-permutation matrices over the complex field C. In this paper we will assume that, G is a p-group of exponent p and class 2, where p is prime and cd(G) = {1, |G : Z(G)|^1/2}. Then we will s...

We demonstrate a new doping scheme where photo-induced carriers from graphene quantum dots (GQDs) can be injected into GaN and greatly enhance photoluminescence (PL) in GaN epilayers. An 8.3-fold enhancement of PL in GaN is observed after the doping. On the basis of time-resolved PL studies, the PL enhancement is attributed to the carrier transfer from GQDs to GaN. Such a carrier transfer proce...

This article reports on the studies of porous GaN prepared by ultra-violet (UV) assisted electrochemical etching in a solution of 4:1:1 HF: CH3OH:H2O2 under illumination of an UV lamp with 500 W power for 10, 25 and 35 minutes. The optical properties of porous GaN sample were compared to the corresponding as grown GaN. Porosity induced photoluminescence (PL) intensity enhancement was found in t...

With an appropriate high anneal temperature under H2 atmosphere, GaN quantum dots (QDs) have been fabricated via GaN thermal decomposition in metal organic chemical vapor deposition (MOCVD). Based on the characterization of atomic force microscopy (AFM), the obtained GaN QDs show good size distribution and have a low density of 2.4 × 10(8) cm(-2). X-ray photoelectron spectroscopy (XPS) analysis...

Gallium nitride (GaN), in contrast to other commonly used piezoceramics, is a semiconductor that exhibits piezoresistive in addition to piezoelectric effects. The large piezoresponse – combined piezoelectric and piezoresistive effects – of GaN points out possible applications of GaN-based material systems in resonant devices. While the static piezoresistive response of GaN is small [1], the tim...

Scanning capacitance microscopy is used to characterize nanoscale, local electronic structure in nonpolar n-type GaN grown in the a-plane orientation using lateral epitaxial overgrowth LEO . Analysis of the bias dependence of the scanning capacitance image contrast observed reveals the presence of a linear, positively charged feature aligned along the 1̄100 direction, extending from an LEO windo...

We have fabricated the vertically aligned coaxial or longitudinal heterostructure GaN/InGaN nanowires. The GaN nanowires are first vertically grown by vapor-liquid-solid mechanism using Au/Ni bi-metal catalysts. The GaN nanowires are single crystal grown in the [0001] direction, with a length and diameter of 1 to 10 μm and 100 nm, respectively. The vertical GaN/InGaN coaxial heterostructure nan...