退火製程影響硫化鎘緩衝層/銅銦鎵硒吸收層介面性質之研究

Application of Rapid Thermal Annealing on CdS Buffer layer/CIGS absorber layer Interface Properties Improvement

鄭家榮(Jia-Rong Jheng)

指導教授 ： 宋家驥

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201703173

摘要

本研究主要的目的為研究退火製程對於CIGS太陽能電池CIGS吸收層與CdS緩衝層介面性質的影響，由於CdS緩衝層/CIGS吸收層介面為異質接面結構，異質結構會造成許多缺陷問題例如：孔洞、晶界、差排等等，這些缺陷會使載子收集困難，降低元件的短路電流，讓元件效能降低。為了改善CdS緩衝層與CIGS吸收層介面的缺陷問題，吾人將CdS/CIGS/Mo/Glass結構進行退火處理，並且利用儀器分析退火製程對於CdS緩衝層/CIGS吸收層介面的影響。
首先，先將Mo背電極濺鍍在蘇打玻璃基板上，接著以濺鍍硒化法成長CIGS吸收層、化學水浴法成長CdS緩衝層，硫化鎘緩衝層成長後將CdS/CIGS/Mo/Glass結構退火，固定升溫速率(1oC/s)、持溫時間(180s)，改變不同退火溫度：150、200、250、300、350oC。當CdS/CIGS/Mo/Glass結構退火之後，以SEM觀察表面形貌、XRD分析晶體結構、XPS檢測CdS緩衝層/CIGS吸收層介面Cd2+、S2-離子擴散情形、PL光致發光影像探討CIGS吸收層發光性質的變化、拉曼光譜分析CdS緩衝層/CIGS吸收層表面分子振動模式。最後，將經過退火及未經過退火的CdS/CIGS/Mo/Glass結構濺鍍ZnO、AZO、Al電極，完成CIGS電池元件的製作，並以太陽光模擬器量測元件之效率參數，比較退火及未經退火的的CIGS元件效率。量測結果顯示，經過退火的CIGS電池結構效率得到改善，當退火溫度為300oC時有最佳之效率，在退火溫度300oC下元件有最大的短路電流，相較於未經退火CIGS元件，改善了4.7%的效率。

關鍵字

薄膜太陽能電池 ； 退火 ； 硫化鎘緩衝層 ； 銅銦鎵硒吸收層 ； 異質接面

並列摘要

The purpose of this research is to investigate the influences of thermal annealing on CIGS absorber layer and CdS Buffer layer interface properties. Since the CdS Buffer/CIGS Absorber is heterojunction structure, there are some defects at CdS Buffer/CIGS Absorber interface. These defects could make the collection of carriers be difficult, and decrease the efficiency of CIGS solar cell. In order to improve the CdS Buffer/CIGS Absorber interface’s defect, we used annealing process on CdS/CIGS/Mo/Glass structure. Then we used instruments to analyze CdS Buffer/CIGS Absorber interface properties.
First, we deposited Mo back contact layer on soda lime glass substrate. Then we deposited CIGS absorber layer by using Sputtering Selenization process; deposited CdS buffer layer by Chemical Bath Deposition. Then annealing process was conducted to anneal CdS/CIGS/Mo/Glass structure. We changed annealing temperatures：150, 200, 250, 300, 350oC and fixed heating rate(1oC/s), holding time(180s). After annealing process, we used SEM to observe the morphology；used XRD to analyze the crystal structure；used XPS to detect the interface diffusion；used PL image and Raman spectroscopy to detect the defect improvement；used Solar Simulator to measure the efficiency of the devices. The results reveals that the annealed CIGS devices had higher efficiency. At annealing temperature 300oC, the CIGS device had most high efficiency. The most high efficiency at this annealing temperature is 9.3%. Compared with no annealing CIGS device, annealed CIGS devices got 4.7% efficiency improvement.

並列關鍵字

CIGS solar cell ； annealing process ； CdS buffer layer ； CIGS absorber layer ； heterojunction structure

參考文獻

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