Noninvasive probing of persistent conductivity in high quality ZnCdSe/ZnSe quantum wells using surface acoustic waves

D. A. Fuhrmann; H. J. Krenner; A. Wixforth; A. Curran; K. A. Prior; R. J. Warburton; J. Ebbecke

doi:10.1063/1.3373415

Noninvasive probing of persistent conductivity in high quality ZnCdSe/ZnSe quantum wells using surface acoustic waves

D. A. Fuhrmann, H. J. Krenner, A. Wixforth, A. Curran, K. A. Prior, R. J. Warburton, J. Ebbecke

School of Engineering & Physical Sciences

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

Attenuation of a surface acoustic wave is used as a highly sensitive and noninvasive probe of persistent photoconductivity effects in ZnCdSe/ZnSe quantum wells. These effects are observed over long time-scales exceeding several minutes at low temperatures. By varying the optical excitation energy and power and temperature we show that these effects arise from carriers photogenerated by interband excitation which are trapped in random potential fluctuations in the quantum wells related to compositional fluctuations. Effects related to defect levels in the band gap can be excluded and a transition of the conduction mechanism with temperature from a hopping to a percolation regime is observed. The transition temperature observed for our quantum well material is strongly reduced compared to bulk crystals. This indicates a superior structural quality giving rise to only weak potential fluctuation of 3 meV. © 2010 American Institute of Physics.

Original language	English
Article number	093717
Journal	Journal of Applied Physics
Volume	107
Issue number	9
DOIs	https://doi.org/10.1063/1.3373415
Publication status	Published - 1 May 2010

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title = "Noninvasive probing of persistent conductivity in high quality ZnCdSe/ZnSe quantum wells using surface acoustic waves",

abstract = "Attenuation of a surface acoustic wave is used as a highly sensitive and noninvasive probe of persistent photoconductivity effects in ZnCdSe/ZnSe quantum wells. These effects are observed over long time-scales exceeding several minutes at low temperatures. By varying the optical excitation energy and power and temperature we show that these effects arise from carriers photogenerated by interband excitation which are trapped in random potential fluctuations in the quantum wells related to compositional fluctuations. Effects related to defect levels in the band gap can be excluded and a transition of the conduction mechanism with temperature from a hopping to a percolation regime is observed. The transition temperature observed for our quantum well material is strongly reduced compared to bulk crystals. This indicates a superior structural quality giving rise to only weak potential fluctuation of 3 meV. {\textcopyright} 2010 American Institute of Physics.",

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AU - Fuhrmann, D. A.

AU - Krenner, H. J.

AU - Wixforth, A.

AU - Curran, A.

AU - Prior, K. A.

AU - Warburton, R. J.

AU - Ebbecke, J.

PY - 2010/5/1

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N2 - Attenuation of a surface acoustic wave is used as a highly sensitive and noninvasive probe of persistent photoconductivity effects in ZnCdSe/ZnSe quantum wells. These effects are observed over long time-scales exceeding several minutes at low temperatures. By varying the optical excitation energy and power and temperature we show that these effects arise from carriers photogenerated by interband excitation which are trapped in random potential fluctuations in the quantum wells related to compositional fluctuations. Effects related to defect levels in the band gap can be excluded and a transition of the conduction mechanism with temperature from a hopping to a percolation regime is observed. The transition temperature observed for our quantum well material is strongly reduced compared to bulk crystals. This indicates a superior structural quality giving rise to only weak potential fluctuation of 3 meV. © 2010 American Institute of Physics.

AB - Attenuation of a surface acoustic wave is used as a highly sensitive and noninvasive probe of persistent photoconductivity effects in ZnCdSe/ZnSe quantum wells. These effects are observed over long time-scales exceeding several minutes at low temperatures. By varying the optical excitation energy and power and temperature we show that these effects arise from carriers photogenerated by interband excitation which are trapped in random potential fluctuations in the quantum wells related to compositional fluctuations. Effects related to defect levels in the band gap can be excluded and a transition of the conduction mechanism with temperature from a hopping to a percolation regime is observed. The transition temperature observed for our quantum well material is strongly reduced compared to bulk crystals. This indicates a superior structural quality giving rise to only weak potential fluctuation of 3 meV. © 2010 American Institute of Physics.

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Noninvasive probing of persistent conductivity in high quality ZnCdSe/ZnSe quantum wells using surface acoustic waves

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