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Article
Electrical, Optical, and Analytical Characterization of Bulk Hydrothermal ZnO Crystals Doped with Indium
Journal of Crystal Growth
  • Buguo Wang
  • Michael J. Callahan
  • Lionel O. Bouthillette
  • David F. Bliss
  • David C. Look, Wright State University - Main Campus
Document Type
Article
Publication Date
1-1-2011
Abstract

Bulk In-doped ZnO crystals have been grown hydrothermally by adding In2O3 to the normal nutrient. The major growth occurs along the [10−10] direction rather than the usual [0001] 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 1.6×1019cm−3 in the bulk, with lesser amounts of Al (2.5×1018), Ga (1.8×1017), Fe (6.5×1018), and Li (1.1×1018). Low-temperature photoluminescence (PL) from the Zn face (0001) shows strong, relatively sharp donor-bound exciton (D°X) lines at 3.3609 and 3.3624eV, attributed to Al and H, respectively, along with much weaker lines at 3.29, 3.22eV, and 2.35eV, 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°X-related PL from the O face (000−1) is much broader because of significantly higher In, Li, and Fe concentrations; however, it also includes a weak, sharp In°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 μ, and resistivity ρ, namely the existence of two flat regions: (1) from 15 to 50K (n=7.8×1018cm−3, μ=48cm2/Vs, and ρ=0.017Ωcm) and (2) from 250 to 320K (n=7.3×1018cm−3,μ=83cm2/Vs, and ρ=0.010Ωcm). A mobility analysis based on degenerate electrons gives donor ND and acceptor NA concentrations of about 1.5×1019 and 7.5×1018cm−3, respectively. Remarkably, within error, ND≈[In]+[Al]+[Ga] and NA≈[Fe]+[Li].

DOI
10.1016/j.jcrysgro.2011.01.065
Citation Information
Buguo Wang, Michael J. Callahan, Lionel O. Bouthillette, David F. Bliss, et al.. "Electrical, Optical, and Analytical Characterization of Bulk Hydrothermal ZnO Crystals Doped with Indium" Journal of Crystal Growth Vol. 319 Iss. 1 (2011) p. 1 - 3 ISSN: 0022-0248
Available at: http://works.bepress.com/david_look/188/