Reduction of crack density in ammonothermal bulk GaN growth

High pressure growth of bulk GaN from solutions in gallium

In this paper, the growth of GaN single crystals from solutions of atomic nitrogen in liquid gallium under high N2 pressure is described. GaN single crystals obtained by the high nitrogen pressure solution method, without an intentional seeding, show strong growth anisotropy, which results in their platelet shape. The attempts to enhance the growth into (0001) directions by the increase of the ...

Near-threshold fatigue crack growth in bulk metallic glass composites

A major drawback in using bulk metallic glasses (BMGs) as structural materials is their extremely poor fatigue performance. One way to alleviate this problem is through the composite route, in which second phases are introduced into the glass to arrest crack growth. In this paper, the fatigue crack growth behavior of in situ reinforced BMGs with crystalline dendrites, which are tailored to impa...

Contactless electroreflectance of AlGaN/GaN heterostructures deposited on c-, a-, m-, and (20.1)-plane GaN bulk substrates grown by ammonothermal method

Optimization of low temperature GaN buffer layers for halide vapor phase epitaxy growth of bulk GaN

We have studied growth and self-separation of bulk GaN on c-oriented Al2O3 using low temperature (LT) GaN buffer layers. By studying the X-ray diffraction (XRD) signature for the asymmetric and symmetric reflections versus the LT-GaN thickness and V/III precursor ratio, we observe that the peak width of the reflections is minimized using a LT buffer thickness of ~100 -300 nm. It was observed th...

Dislocation density reduction in GaN using porous SiN interlayers

The influence of a thin porous SiNX interlayer on the growth of GaN by metalorganic chemical vapor deposition (MOCVD) has been studied. The interlayer is deposited on a GaN template by introducing silane in the presence of ammonia into the MOCVD chamber, and a GaN overlayer is deposited on the interlayer. The SiNX interlayer produces inhomogeneous nucleation and lateral growth of the overlayer,...