Some of the electrical and optical properties of CdZnSSe compound semiconductors

ABSTRACT Ph. D. Thesis SOME OF THE ELECTRICAL AND OPTICAL PROPERTIES OF CdZnSSe COMPOUND SEMICONDUCTORS YASEMİN ÇA?LAR Anadolu University Graduate School of Natural and Applied Sciences Physics Program Supervisor: Prof. Dr. Muhsin ZOR June-2001 In this study, some of the electrical and optical properties of CdZnSSe compound semiconductors have been investigated. The materials have been produced on to the glass substrates by means of the spray-pyrolysis method. The x-rays diffraction spectra of the films have shown that the films so formed are polycrystalline and hexagonal in structure. The material have exhibited direct band gap characteristics with the band gap values lying in the range between 2.38-2.97eV. n-type conduction have been observed in all of the films and their I-V characteristics have shown two different conduction regimes that ohmic and space charged limited. The calculated values of the free carrier concentration and the conductivities varied between 1.2xl08-3xl013cm"3 and l^xlO^-^xKr^Qcm)1, respectively. The calculated values of the activation energies from the Arrhenius plots have been gathered into two groups. The first one, having smaller values ( 0.05-0.1 leV ), is attributed to the ionization energies of donor like states. Whereas the second one, having larger values ( 0.11-0.77eV ), is attributed to the ionization energies arising from the donor-like traps. Keywords: Compound Semiconductors, Spray Pyrolysis, Ohmic Conduction, Space-Charge-Limited Conduction, Donor-Like Traps