The Properties of P-type Cuprous oxide films prepared by reactive sputtering in solar cells application

• Main Authors: Cheng-Kai Yang, 楊程凱
• Other Authors: Tien-Chai Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/8936r6

碩士 === 崑山科技大學 === 電機工程研究所 === 97 === 　Cuprous oxide (Cu2O) is a direct band gap and is p-type semiconductor with a direct band gap of 2.0 eV, and has been attracted to apply in photoelectric devices and chemical catalysis. Cu2O is considered to be an attractive material since it has the advantages of non-toxicity, high absorption coefficient and low-cost producibility. To understand Cu2O characteristics can provide useful and fundamental datum to promote the efficiency of solar cells. The effects of Cu2O thin films deposited by reactive radio-frequency magnetron sputtering were studied. Cu was used as the sputtering target. The RF power and the temperature was changed in order to obtain a cuprous oxide film with different characteristics. The influence of films growing characteristics depended on bias voltage was also discussed. In addition, annealing treatment was used to improve electric properties. In the solar cells parts, we use n-AZO and p-Cu2O films to stack different structure, discusses the cells characteristics of various structure. An α-step equipment was used to detect film thicknesses. A 4-points probe was used to measure the sheet resistivity and Hall measurement was used to detect the carrier concentration and mobility. The structure could be characterized by X-ray diffraction (XRD).The iv surface morphologies were observed by SEM. The transmittance was measured by UV-VIS spectrophotometer. I-V measurement was used to analyzed the I-V curve. The experimental results show that the region grow a single phases of Cu2O films was not easy to control. When process parameters were set at 250℃, the rf power of 160W, the oxygen flow rate of 0.7sccm and the work pressure changed from 5~7mtorr, a single phase of Cu2O films can be obtained. At rf power of 175W, the lowest resistivity of 6Ω-cm, were obtained. The preferred orientation and surface morphologies were significantly changed with bias voltages, therefore, the results show the growth mechanism was also closely relative to bias voltages. The different stacking sequence of n-AZO and p-Cu2O solar cells show a large influence of I-V curve. The device of p-Cu2O on n-AZO to form heterojunction has better characteristic of I-V curve.