Jpn. J. Appl. Phys. 44 (2005) pp. 828-831  |Previous Article| |Next Article|  |Table of Contents|
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Free Carrier Concentration Gradient along the c-Axis of a Freestanding Si-doped GaN Single Crystal

M. Yoon, Il-Woo Park, H. Choi, Sung Soo Park¹ and Eui Kwan Koh

(Received July 2, 2004; accepted October 25, 2004; published February 8, 2005)

The charge carrier concentration variance in a freestanding Si-doped GaN single crystal grown by hydride vapor phase epitaxy (HVPE) has been investigated. A transverse micro-Raman scattering measurement along the [0001] c-axis on the cross section of the n-type GaN was performed to obtain the profile of the free carrier concentration. The analysis of the coupled modes of plasmons and longitudinal optical (LO) phonons revealed the presence of a free carrier concentration gradient along the c-axis, which gradually varies from 2.3×10¹⁷ (N face) to 9.3×10¹⁷ cm^-3 (Ga face). The possible physical origins of the charge carrier concentration gradient in the GaN crystal were discussed on the basis of current theories and experimental results of the growth mechanism of an n-doped GaN single crystal.

KEYWORDS: GaN, hydride vapor phase epitaxy, phonon, Raman scattering
URL: http://jjap.ipap.jp/link?JJAP/44/828/
DOI: 10.1143/JJAP.44.828

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