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HL: Halbleiterphysik

HL 17: Poster Ib

HL 17.37: Poster

Freitag, 4. März 2005, 16:30–19:00, Poster TU F

Photoluminescence properties of ZnO nanowires at low temperatures — •Lars Wischmeier¹, Tobias Voss¹, Ilja Rückmann¹, Sandra Börner², and Wolfgang Schade² — ¹Institut für Festkörperphysik, Universität Bremen, P.O. Box 330440, D-28334 Bremen — ²Institut für Physik und Physikalische Technologien, Technische Universität Clausthal, Leibnizstrasse 4, D-38678 Clausthal-Zellerfeld

Zincoxide nanowires are promising building blocks for miniaturized optoelectronic devices operating in the blue to UV spectral region. Here, the optical properties of such wires with diameters < 200 nm were investigated at low temperatures. The nanowires were grown by a chemical vapor transport and condensation technique on a sapphire substrate.

The photoluminescence (PL) of the nanowire ensemble was measured as a function of temperature (4 - 100 K) and excitation density (up to 7.0 MW/cm²). From the excitation density dependent measurement the P band resulting from the exciton-exciton collision shows a super-linear increase with slope values of ≈ 1 at low densities (< 0.7 MW/cm²) and > 2 at higher densities. For a further emission peak originating from the radiative recombination of donor-bound excitons a linear increase was obtained. The temperature dependence of the shift of the emission energy was in good agreement with the empirical Varshni formula.

In addition results of first micro-PL studies of few to single ZnO nanowires with a spatial resolution on a sub-micrometer scale are presented.