Tuteja Mohit, Mei Antonio B, Palekis Vasilios, Hall Allen, MacLaren Scott, Ferekides Chris S, Rockett Angus A
Department of Materials Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States.
Department of Electrical Engineering, University of South Florida , Tampa, Florida 33620, United States.
J Phys Chem Lett. 2016 Dec 15;7(24):4962-4967. doi: 10.1021/acs.jpclett.6b02399. Epub 2016 Nov 22.
The rear surfaces of CdTe photovoltaic devices without back contacts, grown by close-spaced sublimation (CSS), were analyzed using conductive atomic force microscopy (C-AFM). As-deposited and CdCl-treated CdTe samples were compared to clarify the effect of the treatment on charge flow through grains and grain boundaries. The CdCl-treated samples exhibit a more homogeneous and enhanced current flow across the grains as compared to the as-deposited samples. The grain boundaries show variable current. Under high bias, grain boundaries dominate current flow when the main junction is reverse biased and with the conducting current in reverse breakdown. Under the opposite bias conditions, where the contact of the conductive tip to the surface is reverse biased and under breakdown conditions, the current flow is uniform with little contrast between grains and grain boundaries. The results are interpreted as resulting from the improved crystallinity of the CdTe with reduced p-type doping along the grain boundaries.
使用导电原子力显微镜（C-AFM）对通过近距离升华（CSS）生长的无背接触的碲化镉光伏器件的背面进行了分析。将沉积态和经氯化镉处理的碲化镉样品进行比较，以阐明该处理对通过晶粒和晶界的电荷流动的影响。与沉积态样品相比，经氯化镉处理的样品在晶粒上表现出更均匀且增强的电流流动。晶界显示出可变电流。在高偏压下，当主结反向偏置且传导电流处于反向击穿时，晶界主导电流流动。在相反的偏置条件下，即导电尖端与表面的接触反向偏置且处于击穿条件下，电流流动是均匀的，晶粒和晶界之间几乎没有对比度。结果被解释为是由于碲化镉的结晶度提高，沿晶界的p型掺杂减少所致。
