ABSTRACT
The possibilities for noise spectroscopy of the energy levels in semiconductors are greatly extended if the noise spectra are measured in the photoconductivity regime. Such measurements allow one to detect deep levels and to study their characteristics at a much lower temperature than in the dark. This is of a great importance when studying wide-gap semiconductors. In addition, by analysing the experimental data on photocurrent noise spectra, it is possible to study the particular features of the electron transitions in a photoconductor, to determine the distribution of the recombination flow among the different recombination centers, to ascertain the presence of the infrared (ir) or temperature quenching of photoconductivity, etc. Finally, noise studies allow one to determine which mechanism (concentration or barrier) is responsible for photoconductivity in a given semiconductor material.
Great possibilities for studying the physical processes in illuminated semiconductors are offered by methods based on measurements of the photoluminescence noise characteristics. However, they have not yet been realised. It is hoped that this will be done in the future.
