The effect of gamma radiation on capacitance-voltage parameters of metal/organic/inorganic structures using in solar cells

In this thesis work, Schottky diodes with organic interface have been produced and ionized radiation dependent variations of basic parameters have been investigated. For this, a metal/organic/inorganic structures have been formed by coating a thin organic interface layer on p type silicon substrate. Coronene organic compound has been used as an interface layer and this material has been grown on p type silicon substrate as a thin film by using spin coating method. After formation of omic and rectifier contacts by thermal evaporation technique the voltage dependent capacitance and conductance measurements of structures have been performed at room temperature and in a dark environment. By means of obtained data from the measurements the basic diode parameters have been examined using different techniques. After characterization process, the structures have been exposure to gamma rays of 12 kGy using a 60Co gamma source and the characterization process have been repeated in order to examine the changes of basic parameters after irradiation. The voltage dependent capacitance and conductance curves of structures have been showed a Schottky type behaviour before and after radiation. A decreasing have been occurred in capacitance and conductance values, and an increasing have been occurred in series resistance values of structures after ionized radiation. This case has been attributed to the series resistance effect and formation of acceptor-like interface states generated by radiation. On the other hand, the interface states have been showed a decreasing after irradiation. This has been attributed to pasivation of donor-like interface states by interfacial layer that located on the upper part of the valance band.