No abstract

No abstract

The crystal quality of a-plane GaN films was improved by using epitaxial lateral overgrowth on a nanorod GaN template. The investigation of x-ray diffraction showed that the strain in a-plane GaN grown on r-plane sapphire could be mitigated. The average threading dislocation density estimated by transmission electron microscopy was reduced from 3 ϫ 10 10 to 3.5ϫ 10 8 cm −2 . From the temperature-dependent photoluminescence, the quantum efficiency of the a-plane GaN was enhanced by the nanorod epitaxial lateral overgrowth ͑NRELOG͒. These results demonstrated the opportunity of achieving a-plane GaN films with low dislocation density and high crystal quality via NRELOG.

No abstract

Thick GaN layers have been grown by hydride vapor phase epitaxy (HVPE) on different GaN templates grown by metalorganic vapor phase epitaxy. Crack formation could be reduced by using a hydrogen/nitrogen carrier gas mixture. By carefully optimizing the growth conditions in the final stage of the process, excellent surface morphologies could be obtained at still acceptably high growth rates. Up to 300 µm thick crack-free HVPE layers with a mirror like surface could be grown on our FACELO templates.