Growth of high-quality thick GaN using a tungsten interlayer

A high-quality GaN film was (W-GaN) grown by hydride vapor phase epitaxy (HVPE) on metalorganic chemical vapor deposition (MOCVD) GaN templates with a tungsten (W) interlayer. A sample without interlayer was also grown at the same time for comparison. Significant reductions of dislocation density in W-GaN film is confirmed by the result of high-resolution X-ray diffraction and transmission electron microscope (TEM) observation. The improvement of optical properties of the W-GaN is confirmed by photoluminescence (PL) result. A shift of PL peak suggests that the strain is lower in the W-GaN than the film without W interlayer. This technique offers a potential path to obtain high-quality GaN film as free-standing substrate.