Nitrogen-doped Diamond-Like Carbon fabrication and application to solar cells

• Main Authors: Fu-Ting Hsu, 許富珽
• Other Authors: 徐永富
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/rcngpg

碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 97 === Diamond-like carbon (DLC) thin film has outstanding mechanical strength, wear resistance, and chemical inertness. The purpose of this study is to make use of these properties to enable DLC as a n-type semiconductor for solar cells. Following the example of a-Si:H, such film is applied to amorphous semiconductor with low manufacture cost and high durability. In this study, hydrogen-free DLC thin film was prepared by well-established cathode arc deposition. The binding condition of DLC was controlled by different negative bias on the substrate. According to ESCA analysis, a more negative bias led to a decreased proportion of C-C sp3-bonds, which further enhanced the electrical conductivity of DLC film. Selecting N2 gas as the dopant during the deposition process, nitrogen-doped DLC thin film was successfully prepared. The incorporation of nitrogen atoms into DLC structure was also verified by ESCA analysis. Tested by Hall effect, such DLC film appeared to be one n-type semiconductor. For nitrogen-doped DLC, there existed three binding possibilities between nitrogen and carbon on the ESCA spectrum, namely, N-C sp2-, N-C sp3-, and N-C sp1-bonds. In this case sp1-bonds were outnumbered by the other two categories. From Raman spectra, the relative integration intensity of two kinds of structure, i.e. ID/IG, increased as compared with un-doped DLC. The incorporation of nitrogen lowered the proportion of sp3-bonds. Moreover, slight graphitization in DLC film was observed. After nitrogen-doped DLC was deposited on p-type Si substrate, platinum electrode was subsequently deposited thereon by magnetron sputter, so as to prepare solar cell devices. Either with nitrogen-doped DLC thin film or with p-type Si substrate, it was confirmed that Pt could form an ohmic contact, which has low contact resistance. Under one simulated sunlight illumination of AM 1.5, the lower sp3-bond proportion the nitrogen-doped DLC had, the higher quantum efficiency the corresponding device showed. A photoelectric conversion efficiency of 1.05% was calculated.