PHOTOQUENCHING OF THE HOPPING CONDUCTION IN ARSENIC-ION-IMPLANTED MBEGROWN GAAS

The photoquenching phenomenon in Mott-type hopping conduction below 12 5 K has been observed in As+-ion-implanted molecular-beam- epitaxial G aAs. The photoquenching of the hopping conduction occurs as the implan ted layer changes from amorphous to crystalline by annealing, indicati ng the growth of the AS(Ga) antisite defects as a main component of EL 2. The multiple decay of photoquenching of the conductance with two ti me constants of similar to 22 and similar to 127 s suggests the variat ion of EL2 states arising from the lattice strain due to the excess As . The larger time constant is consistent with the conventional EL2. (C ) 1997 Elsevier Science Ltd.