Minority-carrier transport parameters in CVD diamond

A study is presented on minority carrier transport parameters, in particula r mobility-lifetime products, in natural and CVD diamond materials with dif ferent morphology. mu tau products are obtained by photocurrent versus fiel d measurements and their values rang between 10(-8)-10(-5) cm(2) V-1 depend ing on grain size and orientation. Observed variations are mainly related t o mobility changes, while minority carrier lifetimes are almost constant ar ound 10(-10)-10(-9) s, The origin of such a behaviour is analysed in terms of gap state distribution arising from structural defects, impurities and n on-diamond microphases. (C) 1999 Elsevier Science Ltd. All rights reserved.