Persistent galvanomagnetic effects related to photo-quenching phenomena inlightly n-type LEC GaAs

We investigated the effect of photo quenching on the galvanomagnetic proper ties in Te doped n-type GaAs grown by Liquid Encapsulated Czochralski (LEC) process. Although magnetoresistance coefficient and carrier concentration do not change as a function of photo-quenching time at 55 K, the Hall mobil ity increases with increasing photoquenching illumination time. This result s from the photo-quenching of the EL2 centres. On the other hand, the Hall mobility and carrier concentration increase with increasing photoquenching time at 10 K. These are expected because of the acceptor behaviour of rever se contrast (RC) centres. The magnetoresistance coefficients are constant a t this temperature. Two different kinds of photo-quenching are once again o bserved in lightly n-type GaAs at sample temperature of below 65 K and 40 K from a different aspect using galvano-magnetic effects.