Photoconductivity of Hexagonal Selenium Single Crystals

摘要

A quantitative barrier model of the photoconductivity based on the ideas of Plessner and Stuke has been presented for selenium single crystals. Small angle boundaries have been discovered in the selenium single crystals with the aid of the Guinier-Tennevin method. The existence of the potential barriers most probably associated with the small angle boundaries has been proved indirectly by measuring phonon drag thermopower. This measurement gives support to the result obtained with other selenium crystals that in the temperature range from 80 to 300 degrees K the microscopic mobility of holes is predominantly determined by phonon scattering. The exponential temperature dependence of the d.c. conductivity mobility can thus be explained by potential barriers. From the thermoelectric power measurement the value of the hole concentration is evaluated and is then used in the determination of the photoconductivity parameters. (Author)