Properties of ZnO : Er$^{3+}$ films obtained by the sol–gel method

Polycrystalline and single-phase ZnO : Er$^{3+}$ films are synthesized by the sol–gel method (based on different types of solvents) on surfaces of single-crystal silicon and glass. The electrical measurement data (current–voltage and capacitance–voltage characteristics) show that these ZnO:Al:Er$^{3+}$ films are photosensitive. The introduction of Er$^{3+}$ rare-earth ions into a zinc-oxide film manifests itself in photosensitivity of the current–voltage and capacitance–voltage characteristics to light in the visible and infrared (IR) spectral ranges. The results of this study indicate that ZnO:Al:Er$^{3+}$ films synthesized by the sol–gel method can be used to design optoelectronic devices, in particular, to form solar–cell active layers.