Terahertz Radiation from InAs Films on Silicon Substrates Excited by Femtosecond Laser Pulses

Abstract

Using ultrashort laser pulses, terahertz (THz) emission from InAs thin films grown on Si substrates is investigated. Results show that the measured radiation in transmission geometry exhibits an enhancement of the low frequency components and the strongest emission is from the thickest 520 nm film. Comparison of the emission from a 520 nm film and of bulk GaAs in reflection geometry reveals that the main THz radiation mechanism is the photo-Dember effect. Moreover, comparing the emission from bulk InAs, the thin films can also be categorized as strong THz emitters.