Photoconductivity an Instructive Exercise in Semiconductor Theory

An elementary discussion of photoconductivity is proposed to be a suitable addition to instruction on basic semiconductor theory. A discussion designed for junior electrical engineering students is presented in which photoconductivity is defined and both qualitative and elementary quantitative descriptions are given. A brief look is taken at the energy band structure and impurity levels in germanium, and the application of photoconductivity to infrared detection is considered.