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Carrier density imaging of lateral epitaxially overgrown GaN using scanning confocal Raman microscopy

2001; American Institute of Physics; Volume: 79; Issue: 19 Linguagem: Inglês

10.1063/1.1415421

1520-8842

Manyalibo J. Matthews, Julia W. P. Hsu, Shulin Gu, T. F. Kuech,

ZnO doping and properties

GaN thin films, grown by the lateral epitaxial overgrowth (LEO) method, are studied by scanning confocal Raman microscopy. By measuring changes in coupled longitudinal-optical phonon–plasmon frequencies and using a standard harmonic oscillator dielectric function, detailed images of carrier density could be formed. Carrier concentrations are extremely high (∼1020 cm−3) immediately above SiOx mask layers and decrease abruptly when the SiOx mask are not directly exposed to the growth surface, implying that SiOx masks are the source of dopants. Images of intergrated E1 longitudinal-optical phonon intensities could be compared with free-carrier images and showed a clear anticorrelation throughout the LEO structure.