Electrical Properties of Photosensitive MnFe2O4/n-CdTe Heterojunctions

The manufacturing conditions and electrical properties of photosensitive n-MnFe2O4/n-CdTe isotypic heterojunctions, obtained by the method of spray-pyrolysis of n-MnFe2O4 thin films on the chipped surface of n-CdTe crystalline substrates, were studied. The current rectification ratio was equal to 104 at T = 295 K and voltage |V| = 2 V. The I–V-characteristics of n-MnFe2O4/n-CdTe heterojunctions in the temperature range T = 295–349 K were analyzed and the main current mechanisms at forward and reverse biases were established. Based on the analysis, the role of point defects of cadmium telluride in current generation was clarified. The effect on the C–V-characteristics of the n-MnFe2O4/n-CdTe heterojunction of the series resistance of the structure (RS ≈ 900 Ω), the main component of which is the high-resistance n-MnFe2O4 film (ρ ≈ 106 Ω cm), was revealed. Based on the C–V-characteristics, the main parameters of the heterojunction and the distribution and concentration of the electrically active impurity in the space charge region are determined.