Structure shift of GaN nanowall network, nanocolumn, and compact film were successfully obtained on Si (111) by plasma-assisted molecular beam epitaxy (MBE). As is expected, growth of the GaN nanocolumns was observed in N-rich condition on bare Si, and the growth shifted to compact film when the Ga flux was improved. Interestingly, if an aluminum (Al) pre-deposition for 40 s was carried out pri...

Most III-nitride semiconductors are grown on non-lattice-matched substrates like sapphire or silicon due to the extreme difficulty of obtaining a native GaN substrate. We show that several layered transition-metal dichalcogenides are closely lattice-matched to GaN and report the growth of GaN on a range of such layered materials. We report detailed studies of the growth of GaN on mechanically-e...

GaN is grown by plasma assisted molecular beam epitaxy on ZnO(1 1 00) substrates. Well-oriented (1 1 00) GaN surfaces are obtained, and (1 1 01) oriented facets are also observed. On the GaN(1 1 00) surfaces under Ga-rich conditions a surface reconstruction with approximate symmetry of "4×5" is found. A model is proposed in which this reconstruction consists of 2 ≥ monolayers of Ga terminating ...

Using first-principles theory, we predict ferromagnetism in Cr-doped GaN nanowires irrespective of the sites that the Cr atoms occupy. This is in contrast to Mn-doped GaN nanowires in which the magnetic coupling between the Mn atoms is sensitive to the Mn--Mn and Mn--N distances, although the ground state of Mn-doped GaN nanowires is ferromagnetic. Each Cr atom carries a magnetic moment of abou...

The GaN material parameters relevant to the negative di€erential resistance (NDR) devices are discussed, and their physical models based on the theoretical predictions and experimental device characteristics are introduced. Gunn diode design criteria were applied to design the GaN NDR diodes. A higher electrical strength of the GaN allowed operation with higher doping ( 10 cmÿ3) and at a higher...

We have investigated the growth conditions of cubic GaN (β-GaN) layers on very thin SiC-covered Si(001) by using gas-source molecular beam epitaxy as functions of SiC layer thickness, Ga-cell temperature and substrate temperature. Under the present SiC formation conditions on Si substrates by carbonization using C2H2 gas, the SiC layers with the thickness between 2.5 and 4 nm result in the epit...

(GaN)1-x(ZnO)x solid solution has attracted extensive attention due to its feasible band-gap tunability and excellent photocatalytic performance in overall water splitting. However, its potential application in the photodegradation of organic pollutants and environmental processing has rarely been reported. In this study, we developed a rapid synthesis process to fabricate porous (GaN)1-x(ZnO)x...

AlGaN/GaN HEMT is one of attractive candidates for next generation high power devices because of high carrier mobility in 2DEG channels and high breakdown voltage due high critical electric field. In order to apply the AlGaN/GaN HEMTs for power switching applications the normally off operation is required. Enhancement type behavior of GaN HEMT transistors is obtained by using p-type Mg-doped Ga...

Piezoelectrically actuated micromechanical resonators have been a subject of extensive research for the past decade with the main goal of replacing quartz resonators in timing applications. Aluminum nitride (AlN) has been the main contender as a piezoelectric ceramic replacement for quartz since its low-temperature sputtering process has been developed. In recent years, gallium nitride (GaN) ha...