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A New Technique for Determining Midgap States and Hole Localization in a-Si:H Devices

  • Vikarm L. Dalal (a1) and Ralph D. Knox (a2)

Abstract

We describe a technique for measuring localization of holes in mid-gap states in high quality a-Si:H devices. The localization of holes is determined by measuring quantum efficiency of a-Si:H devices as a function of reverse bias voltage and wavelength of light. It is shown that the QE of localized holes increases significantly upon application of high electric fields, whereas the QE of de-localized holes does not show such a behavior. The voltage-induced increase in QE is explained using a Frenkel-Poole tunneling model. It is also shown that the density of mid-gap states (states in which holes are localized) increases significantly upon light soaking, and that a major consequence of this increase in mid-gap density is a decrease in the electric field in the device. The decrease in electric field is experimentally estimated by fitting the increased current due to tunneling to the expression for Frenkel-Poole tunneling.

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References

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Wronski, C., “Stability of A-Si Alloy Materials and Devices,’ (AIP Proc. #157, AIP, NY, 1987), p. 1.
Stutzmann, M., Jackson, W. B. and Tsai, C. C., Phys. Rev. B 32, 23 (1985).
[3] Gelatos, A. V. and Cohen, J. D., Proc. Mat’l Res. Society, Vol, 118, 141 (1988).
[4] Yamagishi, H., et al., AIP Proc., Vol. 157 , 111 (1987).
[5] Hack, M. and Shur, M., AIP Proc., Vol 157, 134 (1987).
[6] Vaseashta, A., Dalai, V. L., Gruenwald, A. and Halverson, W., Proc. IEEE Photovolt. Conf, (1985), p. 523.
[7] Catalano, A. W., et al., Proc. 19th IEEE Photovolt. Conf., (1987), pp. 1506.
[8] Phillips, J. E. and Roy, M., Proc. 20th IEEE Photovolt. Conf., (1988), pp. 1674.
[9] Dalai, V. L. and Alvarez, F., J. de Physics (Paris), 42 C-4, (1981), pp. 491.
[10] See, for example, Jaros, M., “Physics and Applications of Semiconductor Microstructures,” (Oxford, NY, 1989) pp. 119.
[11] Hack, M. and Shur, M., J. Appl. Phys., 58 , 1656 (1985).

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