非晶矽薄膜太陽能電池的阻礙主要是因為光照衰退( light-soaking)的現象，造成非晶矽薄膜太陽能電池的效率衰減高達 25 % ~ 30 %。傳統上為減輕非晶矽薄膜光衰退現象，常在高溫的環境下通入氫氣以減少非晶矽薄膜內懸浮鍵的數目。而本論文中主要使用室溫下簡單化學浸泡方法減輕在玻璃基板上非晶矽薄膜的光照衰退現象，此方法又稱為氰化處理。 在此用氰化鉀水溶液作為氫化處理的主要溶液，藉著改變濃度與浸泡時間，去找出改善非晶矽薄膜的最佳條件。非晶矽薄膜在經過氰化處理後，由 X-ray光電子能譜( XPS )的 395 eV ~ 406 eV 觀察到 N 1s 的束縛能訊號，證實矽原子有與氰離子形成鍵結 ( Si-CN )。其次使用低溫陰極螢光系統量測非晶矽薄膜的螢光強度，發現隨著濃度提升所量測到的螢光強度越強;螢光強度增加原自於非晶矽薄膜內缺陷減少使得輻射復合數目增加，偵測器接受到的螢光訊號就更強。然後藉由量測光電流與暗電流的比值找到最佳的條件，此條件為非晶矽薄膜在0.4 M 氰化鉀水溶液中浸泡兩分鐘。為了確定氰化處理最佳條件的作用深度，使用XPS量測縱深分佈，在離表面約 15 nm 的位置可以偵測到 N 1s 的訊號。最後，我們將最佳條件應用在非晶矽薄膜太陽能電池上。 The most serious obstacle of hydrogenated amorphous silicon ( a-Si:H ) thin film solar cells is the light-induced degradation; a-Si:H thin film solar cell efficiency will decrease about 25% ~ 30 % during stabilizing. Traditionally, high temperature hydrogen annealing is applied to reduce dangling bonds in the a-Si:H thin films, reducing the light-induced degradation. In this thesis, we want to reduce the light-induced degradation of a-Si:H thin films on glass through a simple room-temperature chemical method, called cyanide treatment. Here the potassium cyanide ( KCN ) aqueous solution is used as the cyanide treatment. We change the concentration of the KCN aqueous solution and immerse time, to find the optimum condition to improve a-Si:H thin film. After cyanide treatment, the combination between silicon atoms and cyanide ion is confirmed by observing the binding energy of N 1s in 395 eV ~ 406 eV through x-ray photoelectron spectroscopy ( XPS ) measurement. Higher radiate recombination with high concentration KCN aqueous solution indicates the reduction of defects in a-Si:H thin films, measured by low temperature cathodoluminescence ( CL ). We found the optimum condition for photocurrent and darkcurrent ratio, when a-Si:H thin film was immersed in 0.4 M KCN aqueous solution in two minutes. In order to determine the penetrating depth of cyanide ion into a-Si:H thin film, the XPS measurement is used to detect the binding energy of N 1s; the signal extends from surface to the depth of 15nm. Finally, we applied the optimum condition for a-Si:H thin film solar cell.
