AVS 57th International Symposium & Exhibition
    Thin Film Thursday Sessions
       Session TF-ThP

Paper TF-ThP18
Photodissolution and Photodiffusion Effects of Silver on Electrical Characteristics of CdTe Thin Film for CdTe/CdS Solar Cells

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Thin Film Poster Session II
Presenter: J.-S. Park, Chosun University, Republic of Korea
Authors: J.-S. Park, Chosun University, Republic of Korea
C.-H. Lim, Chosun University, Republic of Korea
S.-H. Ryu, Chosun University, Republic of Korea
N.-H. Kim, Chonnam National University, Republic of Korea
W.-S. Lee, Chosun University, Republic of Korea
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The maximum efficiency of CdTe/CdS solar cell was just 16.8% although the CdTe thin films shows the excellent absorbance above 99% with only about 2 μm of active thickness. The enhanced electrical characteristics of CdTe thin film are required for the improvement of the efficiency. Doping of polycrystalline CdTe thin film is thought to be one of the effective methods to control the conductivity of CdTe thin film. The group I elements including copper are generally known as substitutional acceptors in CdTe thin films, which increase the p-doping of CdTe thin films. However, there have been many reports on the degradation of solar cell by the high diffusivity of copper. In this study, silver was employed to dope the sputtering-deposited CdTe thin film. Silver was deposited on the 1 μm-thickness of CdTe thin film by the sputtering method with 10 nm-thickness. He-Ne laser (632.8 nm) was exposured with a small energy by a change of exposure time. The remained silver layer was removed with HNO3+3HCl and H2SO4+H2O2 solutions. The photodissolution and photodiffusion effects of silver on the CdTe thin films were investigated by analyzing the electrical and optical properties of CdTe thin films including absorption coefficient, carrier mobility, resistivity and carrier density. AES depth profile was employed to examine the Ag-doped CdTe thin film with a change of He-Ne laser exposure time. Acknowledgement: This work was supported by National Research Foundation of Korea(NRF) grant funded by the Korean Government(MEST) (2010-0016048).