CIGS 태양전지 적용을 위한 레이저 확산법으로 제조한 CdS:In 박막의 특성

Abstract

ABSTRACT

PropertiesofCdS:InThinFilmFabricated by Using Laser Induced Doping Method for CIGS Solar Cells

Myung, Kuk-do Advisor : Prof. Lee, Woo-Sun, Ph D. Prof. Kim, Nam-Hoon, Ph D. Department of Electrical Engineering Graduate School of Chosun University

CdS thin film is a well-known -type semiconductor material. CdS is also widely used material as a window layer with some chalcogenide photovoltaic thin films in the heterostructured solar cells due to its high transmitivity, low resistivity. Cadmium sulfide(CdS) is a direct and wide band gap (2.42eV at room temperature),which is a very desirable window layer for many photovoltaic solar cells including CIGS solar cell. CdS thin film has been paid to the considerable attention due to its band gap, high transmittance, stability and low cost. It is generally known that the undoped CdS thin film has the high electrical resistivity. Indium (In) showed the improvement of resistivity and optical transmittance when it was doped into the sputtering-deposited CdS thin film. In this study, the structural, optical, electrical, and morphological properties of indium-doped CdS thin films were prepared by the effective method with He-Ne laser at roomtemperature. Indium was deposited on the 100nm-thickness CdS thin film by the sputtering method with 30nm-thickness. He-Ne laser (632.8nm) was exposured with a small energy by a change of exposure time. The remain indium layer was removed with the chemical solution. The doping effects of indium on the CdS thin films were investigated by analyzing the structural, optical, and electrical properties of CdS thin films by using X-ray diffraction(XRD), Auger electron spectroscopy(AES), UV-Visible spectrophotometer and Hall effect measurement system. AES depth profile was employed to examine the indium- doped CdS thin film with a change of He-Ne laser exposure time. The doping uniformity and amount of indium into the depth of CdS thin film was compared to the characteristics of CdS thin film. The optimization of indium-doping process was achieved to enhance the electrical and optical characteristics including resistivity and optical transmittance.