表面處理對AZO/Si 異質接面太陽能電池之研究

Abstract

本研究使用三種不同的酸液，分別為緩衝氧化蝕刻液 (BOE)、雙氧水(H2O2) 及稀鹽酸 (HCl) 去除 p 型矽基板上的二氧化矽，並使用直流磁控濺鍍法 (DC Magnetron Sputtering) 製程溫度分別為 298 K 及 573 K ，於基板上沉積一層厚度 100 nm 的 AZO 薄膜，沉積過程通入 40 sccm 的氬氣，之後將 Al 濺鍍在矽基板底部約 1 μm 作為下電極，製備 AZO/Si 異質接面太陽能電池。以穿透式電子顯微鏡 TEM 作結構分析、TEM-EDS 作區域成份分析、電容-電壓及電流-電壓量測儀作電性分析，探討不同表面處理及不同沉積溫度下，對 AZO/Si 異質接面太陽能電池的結構與光電特性的影響。 實驗結果顯示以 H2O2 表面前處理，製程溫度為 573 K 時，在 IPCE 值上有較佳的表現，光電轉化率約 26.6%，且各個波段的轉換效率均大於其他兩項處理材料於該波段下的轉化率，可獲得較佳的光電流約 1.1×10-4 A/cm2。

In this study, for the purpose of removing silicon dioxide on the p-type Si substrate, three different acids were used, buffered oxide etch solution (BOE), hydrogen peroxide (H2O2), and dilute hydrochloric acid (HCl).Additionally, the DC magnetron sputtering method was utilized under the process temperature of 298 K and 573 K. A layer of 100 nm AZO thin film was first deposited on the Si substrate. During the deposition, a flow of 40 sccm argon was infused. Al was sputtered on the bottom of the Si substrate as the bottom electrode. After the AZO/Si heterojunction solar cells were processed, the samples were analyzed in three ways: Transmission Electron Microscope for structural analysis, TEM-EDS for the regional component analysis, and C-V and I-V measurements for electrical analysis. These three methods explored the structure of AZO/Si heterojunction solar cell and the influence of photoelectric properties under different surface treatments and different deposition temperatures.

The experimental results revealed that a better IPCE performance was obtained under H2O2 surface pre-treatment and process temperature of 573 K. Furthermore, the photoelectric conversion rate was about 26.6% and the conversion efficiency of each band was much better than the others. Also, the photocurrent density reached 1.1 × 10- 4 A/cm2.