Photoimpedance spectroscopy of ZnTe/ZnMnTe heterojunction for photodetector devices using Cole–Cole diagrams and relaxation time process

In this work, the heterojunction ZnTe/ZnMnTe/GaAs has been fabricated using the molecular beam epitaxially (MBE) technique. The electric complex impedance has been used to characterize the as-prepared junction at different illumination powers in a wide range of frequencies. It was found that the impedance of the studied junction has the highest value at the darkest point and then decreases with the increase in the applied frequency, illumination power, or both of them. The Cole–Cole diagram showed two relaxation processes for the studied junction for illumination power larger than 10 mWcm⁻². Only one relaxation process has been observed for illumination powers greater than 10 mWcm⁻². The dielectric relaxation time showed an increase with the increase of the illumination power. Accordingly, the prepared heterojunction can be suggested for use as a photo-sensor and/or photo-switch applications.