Abstract

Picosecond photoconductivity studies of ³He⁺ bombarded Fe-doped InP have demonstrated free carrier lifetimes and mobilities of 6 ps and 600 cm²/Vs, respectively^[1]. This result compares very favorably with the 10 ps response time and mobility less than 20 cm²/Vs observed in oxygen irradiated silicon-on-sapphire^[2]. Even when compared to proton irradiated GaAs sampling gates^[3] the He bombarded InP photoconductors demonstrate over an order of magnitude higher peak electrical transmission with comparable sampling apertures and optical pulse energies. Radiation damaged InP appears then to be the more promising material for achieving ultrashort response times and optimum photoconducting sensitivity. In this paper we explore the extent to which the free carrier response time can be reduced by increasing the radiation dose in ion bombarded InP photoconductors. Subpicosecond response times are demonstrated for InP photoconducting sampling gates, but the required radiation doses are found to severely compromise the device sensitivity.

© 1985 Optical Society of America