Photoelectric phenomena in ZnO:Al-p-Si heterostructures

Al-doped zinc-oxide (ZnO:Al) films are obtained by magnetron sputtering. Based on an investigation of electrical properties of the films, it is shown that the electron density in these films is as high as 5x10(20) cm(-3) and is practically constant in the temperature range 77-300 K, which indicates high efficiency of doping ZnO with an Al impurity. It is found that the deposition of thin films (dapproximate to1 mum) on the p-Si(111) surface leads to the formation of heterostructures with the highest photosensitivity of similar to400 V/W at T=300 K, which oscillates in the spectral range 1.3-3.5 eV. With the oblique incidence of linearly polarized radiation, induced pleochroism emerges in such heterostructures. The magnitude of pleochroism oscillates in the range 5-40% (thetaapproximate to75degrees), which is associated with the interference phenomena in the ZnO films. The prospects of using the heterostructures obtained as highly selective photosensors of natural and linearly polarized radiation are considered. (C) 2003 MAIK "Nauka/Interperiodica".