"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Defects induced by ionizing radiations in AII-BVI pollycrystalline thin films used as solar cell materials

S. ANTOHE1,* , L. ION1, V. A. ANTOHE1, M. GHENESCU1, H. ALEXANDRU1

Affiliation

  1. University of Bucharest, Faculty of Physics, P.O.Box: MG-11, Bucharest-Magurele, 077125 Romania

Abstract

Thin films of AIIBVI compounds are potential candidates for the manufacturing of electronic and optoelectronic devices, especially solar cells. In this paper the effects of irradiation with high-energy electrons and protons on structural, electrical and optical properties of CdS and CdSe thin films have been investigated. The films, 1-3 μm thick, were prepared by thermal-vacuum evaporation on glass substrate at a temperature of 220 °C. The samples were irradiated with 6-7 MeV electrons, up to a fluency of 1017 e/cm2 and with 3 MeV protons, up to a fluency of 1013 protons/cm2, respectively. XRD investigation has revealed that the films contain wurtzite-type CdS and CdSe, (001) preferentially oriented in the growth direction. The defects induced by ionizing radiations have been studied by using various techniques: the space-chargelimited- current (SCLC) measurements, the thermally stimulated current spectroscopy (TSC), and the absorption and photoluminscence (PL) spectra measurements. It was found that the electrical conduction of the samples, both before and after irradiation, is controlled by different types of defect distributions, placed in the band gap of the investigated semiconducting layers. Parameters of identified defect levels were determined. A detailed discussion about the possible origin of these defects has been done, suggesting that the mainly defects induced by high-energy electron and proton irradiations are related with chalcogens (S or Se) vacancies. The origin of the other identified defects, with smaller ionization energies, remains unknown at this time..

Keywords

Polycrystalline layers, CdS, CdSe, Electrons and protons irradiation.

Submitted at: Nov. 14, 2006
Accepted at: May 15, 2007

Citation

S. ANTOHE, L. ION, V. A. ANTOHE, M. GHENESCU, H. ALEXANDRU, Defects induced by ionizing radiations in AII-BVI pollycrystalline thin films used as solar cell materials, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 5, pp. 1382-1394 (2007)