本研究首先合成In/Ga比為7:3之CuIn0.7Ga0.3Se2起始粉末，再以不同生坯成型方式成型，探討不同成型方式對CIGS燒結緻密化及微結構之影響。
以熱分解法合成之CIGS粉體為單一相的CIGS黃銅礦結構，經由Scherrer equation計算以及BET比表面積儀的量測結果可以得知所合成出來的粉體屬奈米等級(nanoscale)，但具有相當程度之凝聚。
以乾壓成型法製得CIGS之生坯體於空氣氣氛下進行燒結，由於存在著較高的氧分壓，造成CuSe與Se之偏析；相反的，於真空封管中進行硒氣氛燒結可獲得單一相且維持正常劑量比的CuIn0.7Ga0.3Se2黃銅礦結構之燒結體，但坯體內部仍存在著許多大型凝聚體，伴隨著許多凝聚體間的孔洞(Inter-agglomerate pore)導致坯體無法有效緻密化；此外，於實驗中也發現當做包覆劑及配位溶劑之油胺若於燒結前未完全排除，將阻礙坯體之緻密化產生異常晶粒成長的現象。
以離心成型法製得的生坯，由於大型凝聚體已經透過離心力排除，坯體內部之孔洞主要都是Domain間的小型配位數孔洞(Intra-agglomerate pore)，較利於固相燒結的進行。離心成型坯體經550℃持溫三小時的真空硒化燒結後，坯體已緻密化且晶粒已經成長至數個微米，坯體之相對密度值高達92.3%。
熱壓成型方面，短時間十分鐘的熱壓即可以使坯體之相對密度升高到75%以上，原因為熱壓過程能夠有效的透過外加壓力與持溫受熱過程促進顆粒間的滑移，而能有效的打破凝聚體。而後將經短時間熱壓後的坯體進行真空封管硒化燒結1-3小時後可以使坯體之相對密度提升至91%以上。由UV/VIS光譜量測可以得到經熱壓燒結後之坯體能隙值落在1.15eV。接近CIGS理論最佳轉換效率區間之能隙範圍中。

In this study, CIGS (CuIn0.7Ga0.3Se2) powders synthesized using thermal decomposition method were used as the raw materials to investigate the effects of different forming methods on the densification, crystalline phase and microstructure of CIGS sintered samples.
The CIGS powders synthesized using thermal decomposition method exhibited nano-sized based on the Scherrer’s equation calculation and BET measurements and considerable degree of agglomeration.
The segregations of CuSe and Se were observed in the dry-pressed samples after sintering under air atmosphere due to the volatility of In and Ga. On the contrary, CuIn0.7Ga0.3Se2 chalcopyrite single phase can be obtained, but there were still many inter-agglomerate pores existed in the samples sintered under Se2 atmosphere with encapsulated glass tube. Moreover, it was observed that the oleylamine (acted as the capping agent and coordinated solvent in the thermal decomposition method) existed in the green body due to without completely burning-out before sintering may hinder the densification and inhibit the grain growth.
For the green body prepared by centrifugal forming method, the large agglomerates were removed by centrifugal force, which reduced the amounts of inter-agglomerate pores and hence promoted the densification. The relative density of above 92.3% and grain size of several microns can be obtained for the centrifugal formed sample after sintering at 550oC for 3 h under Se2 atmosphere.
In the case of hot-pressed samples, the relative density of more than 75% can be obtained after hot-pressed sintering for 10 minutes. It may be due to the hot-pressed sintering can effectively break the agglomerates via promoting the slip between the particles by applied pressure. Then, the relative density of CIGS after hot-pressed sintering can be promoted to 91% by sequentially sintering at 550oC for 3 h under Se2 atmosphere. UV/VIS spectroscopy measurements show that the energy gap of the sample after hot pressed and Se2 atmosphere sintering is about 1.15eV, which is close to the theoretical optimum bandgap range of CIGS conversion efficiency.

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