Donor and acceptor concentrations in degenerate InN

A formalism is presented to determine donor (N-D) and acceptor (N-A) concentrations in wurtzitic InN characterized by degenerate carrier concentration (n) and mobility (mu). The theory includes scattering not only by charged point defects and impurities, but also by charged threading dislocations, of concentration N-dis. For a 0.45-mum-thick InN layer grown on Al2O3 by molecular beam epitaxy, having N-dis=5x10(10) cm(-2), determined by transmission electron microscopy, n(20 K)=3.5x10(18) cm(-3) and mu(20 K)=1055 cm(2)/V s, determined by Hall effect measurements, the fitted values are N-D=4.7x10(18) cm(-3) and N-A=1.2x10(18) cm(-3). The identities of the donors and acceptors are not known, although a comparison of N-D with analytical data, and also with calculations of defect formation energies, suggests that a potential candidate for the dominant donor is H. (C) 2002 American Institute of Physics.