Micro-raman investigation of the n-dopant distribution in lateral epitaxial overgrown GaN/sapphire (0001)
- Cite this article as:
- Chaldyshev, V.V., Pollak, F.H., Pophristic, M. et al. Journal of Elec Materi (2002) 31: 631. doi:10.1007/s11664-002-0134-3
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We have investigated the n-dopant distribution in the overgrown and window regions of lateral-epitaxial overgrown GaN/sapphire (0001) using room-temperature micro-Raman spectroscopy in the backscattering configuration. From a fit to the high energy-coupled longitudinal optical (LO) phonon-plasmon mode (LPP+), we have evaluated n ≈ (6.5±0.6) × 1017 cm−3 in the overgrown region; a value considerably higher than that previously reported by Pophristic et al.5 The spectrum from the window region was harder to interpret because of the considerable overlap of the A1(LO) mode and Eg (750 cm−1) sapphire line with the LPP+ trace. The implications of our findings for the overgrown region on the measured thermal conductivity as well as other parameters will be discussed.