Accurate mobility and carrier concentration analysis for GaN

Temperature-dependent mobility mu and carrier concentration n data are simultaneously fitted in a high-quality, n-type GaN layer with wurtzite structure grown by metalorganic chemical vapor deposition. The mobility fit is found to be very important for obtaining the correct acceptor concentration, N-A similar or equal to 1.1 +/- 0.2 x 10(17) cm(-3). Using this range of N-A, a fit to the n vs T curve, corrected for Hall r-factor gives two donor levels of concentration (energy): 2.7 +/- 0.2 x 10(17) cm(-3) (7.5 +/- 1.5 meV) and 1.5 +/- 0.2 x 10(17) cm(-3) (58 +/- 2 meV), respectively. However, the n vs T curve by itself is inadequate for an accurate determination of N-A; in this case, acceptable fits can be obtained for N-A ranging from 0 to 1.2 x 10(17) cm(-3). (C) 1997 Published by Elsevier Science Ltd.