Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
12018889 | Journal of Crystal Growth | 2019 | 6 Pages |
Abstract
Gallium nitride (GaN) films homo-epitaxially grown on GaN/sapphire templates and free standing GaN substrates by plasma-assisted molecular beam epitaxy (PA-MBE) have been investigated. After optimizations of growth temperature, the Ga/N flux ratio, surface preparation as well as initial growth process, the high quality MBE-GaN films were obtained. Combined with X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements, the TD densities were measured â¼4.2â¯Ãâ¯108â¯cmâ2 and â¼5â¯Ãâ¯105â¯cmâ2 for MBE-grown GaN films grown on GaN/sapphire templates and free standing GaN substrates, respectively. The observations of TEM prove the clear interface and well-arranged atomic lattice between substrates and as-grown layers. Besides, a flat and smooth surface with step-flow growth mode is observed by atomic force microscopy (AFM). Photoluminescence (PL) measurements exhibit that the linewidth for free excitons is as narrow as 4â¯meV at low temperature of 8â¯K and the deep level related yellow band emission â¼550â¯nm have been effectively suppressed at room temperature. The process optimization and obtained results give us wide latitude to fabricate high performance devices with lower tolerance to dislocation density.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Yao-Zheng Wu, Bin Liu, Zhen-Hua Li, Tao Tao, Zi-Li Xie, Xiang-Qian Xiu, Peng Chen, Dun-Jun Chen, Hai Lu, Yi Shi, Rong Zhang, You-Dou Zheng,