Semiconductor Photoelectrochemistry

Abstract

This article discusses methods and experimental protocols in semiconductor electrochemistry. The basic principles that govern the energetics and kinetics of charge flow at a semiconductor‐liquid contact are discussed. The principal electrochemical techniques of photocurrent and photovoltage measurements used to obtain important interfacial energetic and kinetic quantities of such contacts are then described in detail. After this basic description of concepts and methods in semiconductor electrochemistry, methods for characterizing the optical, electrical, and chemical properties of semiconductors through use of the electrochemical properties of semiconductor‐liquid interfaces are described. The latter part of this unit focuses on methods that provide information primarily on the properties of the semiconductor surface and on the semiconductor‐liquid junction. In some cases, the semiconductor‐liquid junction provides a convenient method for measuring properties of the bulk semiconductor that can only be accessed with great difficulty through other techniques; in other cases, the semiconductor‐liquid contact enables measurement of properties that cannot be determined using other methods. Due to the extensive amount of background material and the interdisciplinary nature of work in this field, the discussion is not intended to be exhaustive, and the references cited in the various protocols should be consulted for further information. This article covers the following methods in semiconductor electrochemistry: Photoconductor/photovoltage measurements Measurement of semiconductor band gaps using semiconductor‐liquid interfaces Diffusion length determination using semiconductor‐liquid contacts Differential capacitance measurements of semiconductor‐liquid contacts Transient decay dynamics of semiconductor‐liquid contacts Measurement of surface recombination velocity using time‐resolved microwave conductivity Electrochemical photocapacitance spectroscopy Laser spot scanning methods at semiconductor‐liquid contacts Flat‐band potential measurements of semiconductor‐liquid interface Time‐resolved photoluminescence spectroscopy to determine interfacial charge transfer kinetic parameters Steady‐state J‐E data to determine kinetic properties of semiconductor‐liquid interfaces.