a-plane GaN on r-plane sapphire substrates suffers from high density defects and rough surfaces. To obtain pit-free a-plane GaN by metal-organic chemical vapor deposition, we intentionally grew high-temperature (HT) 3-dimensional (3D) GaN buffer layers on a GaN nucleation layer. The effects of the HT 3D GaN buffer layers on crystal quality and the surface morphology of a-plane GaN were studied. The insertion of a 3D GaN buffer layer with an optimum thickness was found to be an effective method to obtain pit-free a-plane GaN with improved crystalline quality on r-plane sapphire substrates. An a-plane GaN light emitting diode (LED) at an emission wavelength around 480 nm with negligible peak shift was successfully fabricated.
Bibliographical noteFunding Information:
This work was supported by the Brain Korea 21 (BK21) program, World Class University (WCU) program (R31-2008-000-10075-0) of the Ministry of Education of Korea, and the Technology Innovation Program (Industrial Strategic technology development program, 10035430, Development of high efficiency light emitting diode for illumination) funded by the Ministry of Knowledge Economy (MKE, Korea).
- Light-emitting diode
- a-plane GaN
- r-plane sapphire