Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.42: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Photoluminescence studies of VPE-grown ZnO nanorods — •H. Gafsi¹, C. Bekeny¹, T. Voß¹, I. Rückmann¹, J. Gutowski¹, A. Che Mofor², A. Bakin², and A. Waag² — ¹Institute of Solid State Physics, University of Bremen, P.O.Box 330 440, 28359 Bremen, Germany — ²IHT, TU Braunschweig, P.O Box 3329,38023 Braunschweig

Capable of emitting UV light ZnO is a promising semiconductor for realizing fully integrated optoelectronic nanodevices. It has a wurtzite crystal structure with a large band gap of 3.37 eV (300 K) and an exciton binding energy of 60 meV, which assures excitonic emission processes still being important at room temperature.

Here, we present temperature dependent PL measurements on ZnO nanorods grown by vapor-phase epitaxy (VPE) on two different substrates, 6H-SiC and a-plane Al₂O₃.

The PL reveals well resolved near-band-gap features, in particular excitonic peaks. Also, it shows phonon-assisted excitonic transitions at temperatures up to about 200 K. On the high energy side of the free exciton at around 3.42 eV an emission band with several fine structure lines is observed whose origin is discussed. Comparing the PL spectra on different substrates, a-Al₂O₃ provides a narrower donor-bound-exciton emission peak than 6H-SiC. Though nominally undoped the rods on 6H-SiC show signatures, which can be attributed to band-to-acceptor transitions. These results demonstrate that by using VPE it is possible to produce nanorods of high quality without using a catalyst.