| Autor: |
Tuteja M; Department of Materials Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States., Mei AB; Department of Materials Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States., Palekis V; Department of Electrical Engineering, University of South Florida , Tampa, Florida 33620, United States., Hall A; Department of Materials Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States., MacLaren S; Frederick Seitz Materials Research Laboratory, University of Illinois , Urbana, Illinois 61801, United States., Ferekides CS; Department of Electrical Engineering, University of South Florida , Tampa, Florida 33620, United States., Rockett AA; Department of Materials Science and Engineering, University of Illinois , Urbana, Illinois 61801, United States. |
| Abstrakt: |
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 2 -treated CdTe samples were compared to clarify the effect of the treatment on charge flow through grains and grain boundaries. The CdCl 2 -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. |
