CHARACTERIZATION OF Al/ZnO/p-Si/Al PHOTODIODE FABRICATED BY SILAR METHOD
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2022
Thesis Language: Turkish
Student: Yasemin ŞAHİN
Supervisor: Şükrü Çavdar
Open Archive Collection: AVESIS Open Access Collection
Abstract:
n this study, undoped and 1%, 3%, 5% cadmium doped zinc oxide thin films were produced on p-type Si at room temperature by Successive Ionic Layer Adsorption and Reaction (SILAR) technique. The structural and electrical properties of the films produced undoped and with different amounts of Cd were investigated. Surface analysis of the produced samples was carried out by scanning electron microscope (SEM). In SEM analysis, it was observed that the surface morphology of the samples changed. Their structural properties were investigated by X-ray diffraction (XRD). It was observed that the crystal size decreased as the Cd contribution increased in the thin films produced in accordance with the XRD results. In the study, the electrical properties of the samples were examined by forming diode structures with undoped Al/ZnO/p-Si/Al and 1%, 3%, 5% Cd doped Al/Cd:ZnO/p-Si/Al and current-voltage (I-V), current-time (I-t) measurements were made in the dark and at different illumination intensities. The ideality factor (n), barrier height (Φb) and saturation current (I0) values of the materials were calculated by using I-V graphs. It was determined that the photocurrent increased with the increase of illumination intensity, the samples were sensitive to illumination and showed photodiode properties. I-t measurements were evaluated to examine the photoresponse feature of the diodes produced and it was observed that the current increased as the illumination intensity increased. Series resistance (Rs) values of undoped and Cd-doped ZnO diodes were calculated using the Norde method and it was determined that the series resistance values were in the Ω range. In the line with the data obtained, it was seen that the electrical properties of ZnO diode structure produced can be changed by changing the amount of Cd doping, and that Cddoped ZnO diodes can be used as photo diodes in optoelectronic applications.
Key Words : ZnO, thin film, diodes, photodiode, Norde method