Surface photovoltage spectroscopy of semiconductor materials for optoelectronic applications

Abstract

Abstract The present contribution reviews the basic principles of the surface photovoltage (SPV) spectroscopy in the metal-insulator-semiconductor operation mode emphasizing on the crucial necessity of combined analysis of the SPV amplitude and phase spectra for the understanding and correct interpretation of the experimental data. Several results are presented obtained by the application of the SPV spectroscopy to semiconductor bulk materials and nanostructures designed for applications in optoelectronic devices. These include: (i) AlAs/GaAs superlattices with GaAs embedded quantum wells for optical emitters, (ii) multilayer structures with InAs/GaAs submonolayer quantum dots for infra-red photodetectors, (iii) Si nanowires for light trapping in solar cells and (iv) dilute nitrides Ga(In)As(Sb)N layers for photovoltaic applications. Valuable information about the investigated materials is obtained such as the optical absorption spectrum defined by the quantum confinement and excitonic effects, the optical transition energies, the effect of surface states on the minority carrier diffusion length, the type of the residual doping in the layers, and the alignment of the energy bands across the structures. It is shown that the SPV spectroscopy is a powerful highly sensitive non-destructive technique for room temperature characterization of various semiconductor materials applied in optoelectronics.