Photocurrent Relaxations and Gain in Semiconductor Nanowires

In this paper we study the transient and steady-state photoconductivity of semiconductor nanowires by putting forward the importance of surface recombination in the photocurrent formation. The phenomenological model based on existence of radius and time dependent surface band bending is able to explain both the dark conductivity and dynamics of photoconductivity transients in semiconductor nanowires. The dependence of the variation of surface recombination barrier height on the carrier capture by surface states leads to a non- exponential character of photoconductivity kinetics. Analytic equations are derived to calculate current-voltage and lux-ampere characteristics, photocurrent relaxation and gain under the excitation of light pulses. The analytical results are compared with the experimental data.