ZnO∶Al薄膜中本征缺陷对光电效应的影响

Effect of the Intrinsic Defects in ZnO∶Al Films on Photoemission

在直流溅射法制备ZnO薄膜的过程中 ,通过合适选取溅射时氧氩的压力比 ,可以显著提高所得n ZnO p Si异质结的光生短路电流 ,并且对该异质结的光生开路电压没有明显影响 ,从而可以用这种方法明显提高其光电转化能力。即使是在已经进行了n型掺杂的ZnO薄膜 (这里为ZnO∶Al)中 ,改变溅射时氧氩比对光电效应的影响也很明显。通过实验 ,已经证实了产生这种现象的原因是溅射时氧氩比的改变导致了ZnO薄膜内部的本征缺陷浓度的改变 ,使得载流子浓度变化而导致的结果。在氧氩压力比约为 1∶3时 。

The photoelectric translating efficiency of the ZnO film is a very important parameter of ZnOs photoelectric characters, which especially is useful on solar cells. Generally the photoelectric property of ZnO can be enhanced by using n type impurity dopants. But we discovered that the intrinsic defects can still make effective action even if the ZnO have doped by n type impurity dopants. In the process of DC reactive sputtering, an appro priate pressure proportion of O 2 and Ar will lead to an distinguished increase in the short circuit photocurrent of the n ZnO/p Si heterostructure, on the other hand, it shows very little effect on open circuit photovoltage. Even if the ZnO film have been doped with n type impurity dopants, the photoelectric translating efficiency of the ZnO film will reveal a sensitivity to the change of the O 2 and Ar proportion. Also, we have proved that this phenomenon is the final result of the deviation of the O 2 and Ar proportion in the DC reactive sputtering process, which consequently causes a change in the concentration of the n type carrier(electron) and the short circuit photocurrent of the n ZnO/p Si heterostructure. Finally, we found that the photovoltage translating efficiency reaches its maximum value when the proportion of O 2 and Ar is about 5∶3.