標題: Fabrication and lasing characteristics of GaN nanopillars
作者: Lo, Ming-Hua
Cheng, Yuh-Jen
Kuo, Hao-Chung
Wang, Shing-Chung
光電工程學系
Department of Photonics
關鍵字: GaN nanopillar;GaN laser;excitonic emission
公開日期: 2011
摘要: We report the fabrication of GaN nanopillars and their laser action characteristics under optical pumping measurement. The nanopillars were fabricated from a GaN epitaxial wafer by self-assembled Ni nanomasked etching, followed by epitaxial regrowth to form crystalline facets on the etched nanopillars. The regrowth process is intended to reduce surface defects created during ICP-RIE etching. The density of etched GaN nanopillars is about 8.5x10(8)/cm(2) and the diameter and height of GaN nanopillars are about 250 nm and 650 nm, respectively. The as grown GaN nanopillars exhibit a random distribution with hexagonal pillar geometry. The sample is optically excited by frequency tripled Nd:YAG pulsed laser. The Gaussian waist of pumping spot is 1.8 um. At low pumping intensity, the emission has a broad spontaneous emission spectrum with maximum at 363 nm. As pump intensity increases, a narrow peak at 363 nm emerges quickly from the broad spontaneous emission back ground. The lasing action occurs at threshold pump power density of 122 MW/cm(2). The emission linewidth decreases with pumping power across threshold and reaches a lowest value of about 0.38 nm above threshold. The excitation-power-dependent spectra show that the lasing wavelength has a slight blue shift as pump power increases. We remark that this is due the band filling of the increasing excited carrier density.
URI: http://hdl.handle.net/11536/14985
http://dx.doi.org/10.1117/12.874151
ISBN: 978-0-81948-476-5
ISSN: 0277-786X
DOI: 10.1117/12.874151
期刊: GALLIUM NITRIDE MATERIALS AND DEVICES VI
Volume: 7939
Appears in Collections:Conferences Paper


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