Modificări fotoinduse în stările de suprafaţă în structurile poroase de InP

Abstract

In this paper we present the results of the exploration of n-InP membranes with honeycomb porous structure. The samples were obtained via electrochemical anodization of n-InP:S substrates in solution of HCl in water. Substrates with various orientations and carrier concentrations were used. The obtained porous membranes were then investigated using THz Time Domain Spectroscopy setup (TDS) and X-ray Photoemission Spectroscopy (XPS). After photoexcitation with wavelength radiation of 800 nm it was observed a quasi irreversible increase of the dark conductivity. After a few hours the conductivity received its original state. An electronic density calculation for different pinning energies suggests that the photoexcitation can reduce the density of surface states.