Effect of temperature on the current transfer mechanism in the reverse I-V characteristics of the n-CdS/i-CdSxTe1-x/p-CdTe heterostructure

In this work, we study the influence of the temperature on the mechanism of current transfer in the reverse branch of the current-voltage (I-V) characteristics of n-CdS/p-CdTe heterostructures. The study of the heterostructure, using the technique of on energy-dispersive X-ray analysis, showed that a layer of CdSxTe1-x is formed at the boundary of the heterojunction with a varying composition, being equal x approximate to 0:48 from the side of CdS and x approximate to 0:02 from the CdTe side. In the studied range of the temperatures and bias voltage, the current-voltage characteristics are described well by a power law J = AV(alpha), where the exponent alpha changes with the temperature and voltage. Under the influence of the temperature and charge carrier concentration, the mechanism of current transfer in the structure changes from exclusion (alpha approximate to 0:5) to ohmic (alpha approximate to 1), and then goes to injection (alpha approximate to 2). The inhomogeneous intermediate CdSxTe1-x i-layer at the boundary of the n-CdS/p-CdTe heterostructure is characterized by the presence of metastable states that rearrange at high temperatures and certain charge carrier concentrations. As a result of this, the exclusion slows down and electrons are injected from the rear molybdenum contact.