Control of valence band offset of Cu(In,Ga)Se2 solar cells with single-graded band profile
Control of valence band offset of Cu(In,Ga)Se2 solar cells with single-graded band profile
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DOI：
10.7567/jjap.56.062301
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发表时间：
2017-05
影响因子：
1.5
通讯作者：
Tomohiro Ogihara;Adiyudha Sadono;Takahito Nishimura;Kazuyoshi Nakada;A. Yamada
中科院分区：
文献类型：
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作者：
Tomohiro Ogihara;Adiyudha Sadono;Takahito Nishimura;Kazuyoshi Nakada;A. Yamada
我们已经发现，在CdS/Cu（In，Ga）Se 2界面处插入Cu（In，Ga）3Se 5层对于在低温下制备的具有单梯度带分布的Cu（In，Ga）Se 2太阳能电池的效率是有效的。虽然在600 °C左右生长的Cu（In，Ga）Se 2太阳能电池通常采用双梯度分布，但由于能带分布的可控性更高，单梯度分布更适合于低温生长的太阳能电池。我们还分析了Cu（In，Ga）3Se 5层的作用，通过透射电子显微镜能量色散X射线谱（TEM-EDX）和扫描电子显微镜电子束感生电流（SEM-EBIC），发现Cd扩散到Cu（In，Ga）3Se 5层，导致pn结电界面从高度缺陷的结构界面的移位。最后，通过应用这种新的谱带分布，VOC和FF增加，导致在450 °C的衬底温度下效率从13.4%提高到14.5%。
We have revealed that the insertion of a Cu(In,Ga)3Se5 layer at the CdS/Cu(In,Ga)Se2 interface is effective for improving the efficiency of Cu(In,Ga)Se2 solar cells fabricated at low temperatures and with single-graded band profiles. Although the double-graded profile is usually adopted for Cu(In,Ga)Se2 solar cells grown at around 600 °C, the single-graded profile is more suitable for low-temperature-grown solar cells owing to the higher controllability of band profiling. We also analyzed the role of the Cu(In,Ga)3Se5 layer by transmission electron microscopy energy-dispersive X-ray spectrometry (TEM–EDX) and scanning electron microscopy electron-beam-induced current (SEM-EBIC), and found that Cd diffuses to the Cu(In,Ga)3Se5 layer, resulting in a shift of the pn-junction electrical interface from the highly defective structural interface. Finally, by applying this new band profile, VOC and FF increased, resulting in an efficiency improvement from 13.4 to 14.5% at a substrate temperature of 450 °C.