Using the sol-gel method, strontium titanate films were prepared
(strontium titanate xerogels) on monocrystalline silicon substrates at 750°C
annealing temperature. Nickel upper electrodes were deposited by
magnetron sputtering, and the current–voltage characteristics were
measured for the prepared structures with two upper electrodes and a
Schottky barrier. Significant changes in the current–voltage characteristics
were observed after illuminating the diode structure with a halogen lamp
characterized by 57 mW/cm2 intensity and 3123°C color temperature of the
tungsten filament. For a 65-nm thick strontium titanate film under reverse
bias voltage of –3 V the photocurrent is 80 μA, whereas without illumination
the reverse current is close to zero. Under direct illumination and a voltage
of 3 V the photocurrent is 190 μA, while without illumination the current
does not exceed 22.5 μA
