Continuous wave OSL in bulk AlN single crystals

Deep-uv Transparent Bulk Single-crystalline Aln Substrates

Bulk aluminium nitride (AlN) is a very promising substrate material for UV optoelectronics based on AlGaN ternary compounds. AlN single crystals exceeding 1'' in diameter can now be grown by physical vapour transport (PVT). UV transparency is of high interest for UV devices designed to emit through the substrate. We report on 500 μm thick bulk AlN substrates with plain UV transmittance of 50% (...

Bulk AlN single crystal growth on foreign substrate and preparation of free-standing native seeds

Physical vapour transport growth of aluminium nitride (AlN) single crystals on silicon carbide (SiC) substrates has been optimised and crack-free, large-area, free-standing (0001) AlN wafers were prepared from the grown template crystals. 28 mm diameter single crystals without any polycrystalline surroundings were obtained. Different off-oriented substrates give rise to different growth modes. ...

AlGaN/GaN Heterostructure Field-Effect Transistors on Single-Crystal Bulk AlN

Hopping Conductivity in Single Crystals (Cd0.6Zn0.32Mn0.08)3As2 (RESEARCH NOTE)

The growth processes of Tetragonal single crystals of solid solution (Cd0.6Zn0.32Mn0.08)3As2, space group P42/nmc, has been synthesized by Bridgman method. Conductivity and magnetoresistance of (Cd0.6Zn0.32Mn0.08)3As2 were measured in the range 1.6K to 300K and in magnetic field up to 25 T. Crossover from Mott variable-range-hopping conductivity mechanism close to helium temperatures. In this w...

Vacancy defect distributions in bulk ZnO crystals

We have used positron annihilation spectroscopy to study vacancy defects in ZnO single crystals grown by various methods from both commercial and academic sources. The combination of positron lifetime and Doppler broadening techniques with theoretical calculations provides the means to deduce both the identities and the concentrations of the vacancies. The annihilation characteristics of the Zn...