ON THE EFFECT OF SURFACE-STATES ON PHOTOC URRENT KINETICS IN THE SURFACE-BARRIER MIS TUNNEL STRUCTURES

Recharging of surface electron states has been theoretically studied f or its effect on photocurrent kinetics in the surface-barrier MIS tunn el structures under modulated illumination. The displacement current i s shown to substantially change photocurrent relaxation kinetics when conditions are close to the shorting. Then time of photocurrent transi tion to a steady state is tau(w), the time of capacitance recharging f or space-charge region in a semiconductor. The only exception is the c ase when effective rate of surface recombination is equal to or greate r than the effective rate of minority carriers now into contact. For t hat case the photocurrent, after switching on illumination, firstly re aches (in time tau(w)) the value of photogeneration current and then i s relaxing to a stationary value, the time or the last process being d etermined by surface states parameters.