Carrier dynamics studies through free-carrier absorption: a Monte Carlo study for silicon

Monte Carlo based computer simulations normally used for transport studies in semiconductors are extended and used to study free-carrier absorption of subbandgap radiation in semiconductors. The approach is applied to n-type silicon where we find very good agreement with experimental results and calculations based on quantum electrodynamics. The computer simulation method also allows us to study free-carrier absorption in semiconductors with a dc bias. We solve the classical transport equation to show that the absorption coefficient in the presence of a dc bias can be used to obtain information on the carrier temperature, momentum relaxation time, as well as energy relaxation time. Monte Carlo studies show this to be the case. Thus, we show that important carrier dynamics properties can be obtained from long-wavelength free-carrier absorption studies done on samples with a dc bias.