Enhancement of the photoconductivity in 2D photonic macroporous silicon structures

摘要

Effects of the enhancement of photoconductivity in 2D photonic macroporous silicon structures were investigated. Dependence of photoconductivity on the angle of incidence of the electromagnetic radiation is observed with maxima at normal incidence of electromagnetic radiation, in the region of the angle of full internal reflection respective to macropore walls and at a grazing angle of incidence respective to the surface of structure. The absolute maximum of photoconductivity is measured at distance between macropores, corresponding to two lengths of the electron free run, i.e. by the maximal transfer of the amplified electric components from a macropore surface in a silicon matrix. Angular dependences of photoconductivity, as well as enhancement of the photoconductivity in comparison with monocrystal silicon, primary absorption p-component of electromagnetic radiation testified to formation of surface electromagnetic waves in illuminated macrporous silicon structures. Its effects result in amplification of a local electric field on a surface of macroporous silicon structure and a macropore surface. The measured value of the built-in electric field on a macropore surface achieves 10~6 V/cm, the signal of photoconductivity amplifies 10~2 times, and Raman scattering - up to one order of value.