Bulk In-doped ZnO crystals have been grown hydrothermally by adding In2O3 to the normal nutrient. The major growth occurs along the [1 0 -1 0] direction rather than the usual [0 0 0 1] and [000 - 1] directions; thus, a c-plane crystal has a plate-like shape. Secondary-ion mass spectroscopy (SIMS) measurements reveal an In concentration of about 1.6 x 10(19) cm(-3) in the bulk, with lesser amounts of Al (2.5 x 10(18)), Ga (1.8 x 10(17)), Fe (6.5 x 10(18)), and Li (1.1 x 10(18)). Low-temperature photoluminescence (PL) from the Zn face (0 0 0 1) shows strong, relatively sharp donor-bound exciton (D degrees X) lines at 33609 and 3.3624 eV, attributed to Al and H, respectively, along with much weaker lines at 3.29, 3.22 eV, and 2.35 eV, tentatively assigned, respectively, to a 1-LO-phonon replica of the D X transitions, a donor-acceptor-pair transition, and the usual green band of unknown origin. The D degrees X-related PL from the 0 face (0 00 - 1) is much broader because of significantly higher In, Li, and Fe concentrations; however, it also includes a weak, sharp In degrees X line evidently emanating from the bulk region. The Hall-effect measurements in the range 15-320K reveal an unusual temperature variation of carrier concentration n, mobility mu, and resistivity rho, namely the existence of two flat regions: (1) from 15 to 50 K (n=7.8 x 10(18) cm(-3), mu=48 cm(2)/V s, and rho=0.017 Omega cm) and (2) from 250 to 320 K (n=7.3 x 10(18) cm(-3), mu=83 cm(2)/V s, and rho = 0.010 Omega cm). A mobility analysis based on degenerate electrons gives donor N-D and acceptor N-A concentrations of about 1.5 x 10(19) and 7.5 x 10(18) cm(-3), respectively. Remarkably, within error, N-D approximate to [In]+[AI]+[Ga] and N-A [Fe] + [Li] (C) 2011 Elsevier B.V. All rights reserved.