Study of the microstructure and characterization for GeSbTe solar cell

• Main Authors: Jian-Cheng Chu, 朱健誠
• Other Authors: Shea-Jue Wang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/ex9vfu

碩士 === 國立臺北科技大學 === 材料及資源工程系研究所 === 100 === This study examined that the single layer GeSbTe films and bi-layer GeSbTe films were deposited by the DC-sputtering system. The better crystalline properties were obtained by improving with bi-layer fabrication process. The film was prepared by sputtering system with dc power of 15W. The deposited films were made with single layer and bi-layer structure, heated with two conditions, direct heating and post annealing. In bi-layer films, the first layer onto substrate and second layer film are heated with various heating sequence under the above conditions. The deposited films were confirmed by x-ray diffraction, scanning electronic microscopy, UV-visible spectrometer, and Hall measurement. The single layer GeSbTe films show less intensity of diffraction peaks. The annealing or directly heating samples both show Ge2Sb2Te5 phase through XRD. However the annealing samples have obvious diffraction peaks. The SEM figures display that the single GeSbTe film thick is 60nm, bi-layer GeSbTe films have many grain boundaries after twice annealing on surface. The UV-visible spectrum shows that the grain boundaries result in decreasing the transmittance. The electrical property of the films with bi-layer structure which was directly heating for the first layer and the post annealing for second show that bi-layer GeSbTe films through Hall measurement has the higher carrier concentration. The cell structure is stacked ITO/GST/n-Si/Cr. The device with bi-layer GeSbTe films with two post annealing steps during 150℃ for 30 minutes has achieved 0.311％ conversion efficiency in its stack-junction solar cell.