Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8149200 | Journal of Crystal Growth | 2016 | 11 Pages |
Abstract
Selective area growth (SAG) of high-density (2.5Ã109Â cmâ2) GaN nanowires (NWs) on Si(111) substrate by plasma-assisted molecular beam epitaxy is presented. The effects of morphology and thickness of the AlN seeding layer on the quality of SAG GaN NWs are investigated. A thin AlN seeding layer of 30Â nm thick with a surface roughness of less than 0.5Â nm is suitable for high quality SAG GaN NWs growth. High-density AlN nanopedestal arrays used as seeds for SAG GaN NWs are fabricated from thin AlN seeding layers using soft nanoimprint lithography. By adjusting the growth temperature and Ga/N flux ratio, hexagonal shaped SAG GaN NWs are realized. The quality of SAG GaN NWs is evaluated by low temperature photoluminescence (PL) measurements. Three major groups of PL peaks at 3.47, 3.45, and 3.41Â eV are identified. The peak at 3.471Â eV is related to the neutral donor-bound exciton emission, and the 3.41Â eV broadband emission is attributed to stacking faults or structural defects. The 3.45Â eV peak is identified as the emission due to exciton recombination at polar inversion domain boundaries of NWs.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
C.H. Wu, P.Y. Lee, K.Y. Chen, Y.T. Tseng, Y.L. Wang, K.Y. Cheng,