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Armenian Journal of Physics=Ֆիզիկայի հայկական հանդես
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Title:
TRANSIENT AND STATIONARY PHOTOCONDUCTIVITY OF SEMICONDUCTOR NANOWIRES
Creator:
S. G. Petrosyan ; S. Nersesyan ; A. Yesayan
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Abstract:
We developed an analytical model for the photoconductivity (PC) of semiconductor nanowires (NWs). The model takes into account the enhanced role of surface recombination in the lifetime of nonequilibrium carriers in NW due to large surface-to-volume ratio. The main peculiarities of the NW PC are governed by radius and time dependent recombination barrier, which varies in time with interplay between the NW quasi-neutral core radius and the space charge layer thickness near the surface. Assuming acceptor-like-traps located on the surface of NW we find the relationship between the thickness of space-charge region and nonequilibrium surface charge density in NW and thus calculate the size-dependent PC. Time variation of surface band bending in the course of carrier capture by surface states leads to a non-exponential character of transient PC. The instantaneous relaxation time grows with time after turning of the illumination and it can become so large that persistent PC can be observed even at room temperatures. The results are in good agreement with available experimental data.