The possibility of obtaining a detailed picture of the electronic structure makes surface photovoltage spectroscopy (SPS) eminently suitable for bridging the gap between the chemical, physical, optical and electrical properties of semiconductors. In SPS, changes in band bending (both at the free semiconductor surface and at buried interfaces) are monitored as a function of external illumination. Surface photovoltage spectroscopy can provide detailed, quantitative information on bulk properties (e.g. bandgap and type, carrier diffusion length and lifetime) and can be used for complete construction of surface and interface band diagrams, including the measurement of energy levels in quantum structures. A particular strength is that a comprehensive analysis of surface and bulk defect state distributions and properties is made possible. Measurements using SPS are contactless and non-destructive. In addition, they can be performed both in situ and ex situ, at any reasonable temperature, on any semiconducting material, at any ambient and at any lateral resolution down to the atomic scale. This review starts with an overview of SPS-related surface and interface theory, describes the SPS experimental set-up and presents applications for surface and interface characterization of a wide variety of materials and structures, cross-correlating them with other methodologies.
- Semiconductor structures
- Surface photovoltage spectroscopy