Jakub Zdziebłowski
supervisor: Paweł Zabierowski
Cadmium indium sulfide (CdIn2S4) is a chalcogenide semiconductor material, in which past re-search found effects characteristic for devices exhibiting memristive properties i.e. resistive switching and memory effect.
This work focus on optoelectronic research of CdIn2S4 thin-films for application in memristive devices. Photosensitivity creates a possibility to apply CdIn2S4 in phototunable resistive switch-ing devices – a novel growing field on the verge of photonic and neuromorphic computing.
Thin-film layers of annealed polycrystalline CdIn2S4 were prepared. We measured photocurrent kinetics at various wavelengths in visible and IR band in temperature ranges of 100-300K. Hence, we acquired wavelength-dependent resistivity relationship and basic information about band structure. Bandgap energy and conductivity dependence of the annealing process and significant change in spectral response after pre-irradiation of the sample were obtained.
We propose a consistent model describing photoconductivity change controlled by Fermi level pinning among samples of various stoichiometry. Finally, we found, that photoconductivity in-creases significantly after sample pre-illumination. The effect is persistent and vanishes gradually along with temperature increase. Thus, it implies a high impact of metastable defects on sample behaviour. This phenomenon can be turned off by lowering Fermi energy, which gives approxi-mate location of the responsible defect or defect complex.