標題: Thickness effect on ultrafast thermalization of carriers in above-band-gap states in ZnO epitaxial films
作者: Ou, Po-Chi
Lin, Ja-Hon
Chang, Chi-An
Liu, Wei-Rein
Hsieh, Wen-Feng
光電工程學系
Department of Photonics
公開日期: 15-Dec-2010
摘要: Energy-dependent free-carrier dynamics was investigated in 70 nm (thin) and 1 mu m (thick) ZnO epifilms using the optical pump-probe technique. The far-above-band-gap dynamics in the thin epifilm reveals the prolonged relaxation and the slow recovery of renormalized band gap. The band-gap renormalization (BGR) effect is affected by the inefficient carrier-phonon scattering. In addition, the loss of excited carrier density via surface trapping results in an energy-dependent BGR buildup time. However, the far-above-band-gap dynamics in the thick epifilm reveals fast relaxation followed by BGR recovery, which is independent of the photon energy. The near-band-gap dynamics shows an ultrafast carrier thermalization both in the thin and the thick epifilms.
URI: http://dx.doi.org/10.1088/0022-3727/43/49/495103
http://hdl.handle.net/11536/26224
ISSN: 0022-3727
DOI: 10.1088/0022-3727/43/49/495103
期刊: JOURNAL OF PHYSICS D-APPLIED PHYSICS
Volume: 43
Issue: 49
結束頁: 
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