Gallium nitride microcavities formed by photoenhanced wet oxidation

Journal Article · Mon Oct 17 04:00:00 EDT 2005 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2103423· OSTI ID:20706374

Peng, L -H; Lu, C -Y; Wu, W -H; Wang, S -L ^[1]

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1. Department of Electrical Engineering and Institute of Electro-Optical Engineering, National Taiwan University, Taipei, Taiwan (China)

We report the formation of gallium nitride (GaN) microcavities by manipulating a photoenhanced oxidation rate difference between the polar and nonpolar crystallographic planes of GaN. When immersed in a buffered acetic (CH{sub 3}COOH) electrolyte of pH{approx}6.2 at room temperature, it is shown that the photo-oxidation can proceed at a rate that is one order of magnitude slower on the nonpolar plane of {l_brace}1100{r_brace}{sub GaN} than on the polar plane of {l_brace}0001{r_brace}{sub GaN} due to the reduced surface field action. Gallium nitride microcavities bounded by optically smooth {l_brace}1100{r_brace} and {l_brace}1103{r_brace} facets can thus be preferentially formed on the c-plane sapphire substrate after dissolving the oxide layer. The optical properties of these GaN hexagonal cavities reveal characteristic peaks of whispering gallery modes in resonance with the GaN band edge emission spectrum. A typical cavity Q factor of 10{sup 3} is observed in these GaN microcavities due to a reduced optical scattering loss in the wet chemical reaction process.

• OSTI ID: 20706374
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 16 Vol. 87; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALLOGRAPHY
ELECTROLYTES
EMISSION SPECTRA
GALLIUM NITRIDES
LAYERS
OPTICAL PROPERTIES
OXIDATION
OXIDES
PHOTOCHEMISTRY
SAPPHIRE
SEMICONDUCTOR MATERIALS
SUBSTRATES
TEMPERATURE RANGE 0273-0400 K