CdTe thin film solar cells have demonstrated high scalability, high efficiency and lowcost fabrication process. One of the key factors for the achievements of this technology is the transformation of the absorber layer by an activation treatment where chlorine reacts with CdTe in a controlled atmosphere or in air, improving the electrical properties of the absorber and enhancing the intermixing of the CdS/CdTe layers. With this work we study the activation process by analyzing the CdCl2 treatment made by wet deposition with different annealing temperatures from310 °C up to 410 °C in air keeping the same CdCl2 concentration inmethanol solution. In this way the whole dynamic of the chemical reaction from the minimumactivation energy is analyzed. Activated CdTe layers have been analyzed by means of X-ray diffraction and atomic forcemicroscopy. Finished deviceswith efficiencies from 8% for the low temperature annealing up to more than 14% for the high temperature ones have been thoroughly analyzed by current–voltage, capacitance–voltage and drive-level capacitance profiling techniques. The best performance has been achieved with an annealing temperature of 395 °C.
CdCl2 activation treatment: A comprehensive study by monitoring the annealing temperature
RIMMAUDO, Ivan;SALAVEI, Andrei;PICCINELLI, FABIO;DI MARE, Simone;ROMEO, Alessandro
2015-01-01
Abstract
CdTe thin film solar cells have demonstrated high scalability, high efficiency and lowcost fabrication process. One of the key factors for the achievements of this technology is the transformation of the absorber layer by an activation treatment where chlorine reacts with CdTe in a controlled atmosphere or in air, improving the electrical properties of the absorber and enhancing the intermixing of the CdS/CdTe layers. With this work we study the activation process by analyzing the CdCl2 treatment made by wet deposition with different annealing temperatures from310 °C up to 410 °C in air keeping the same CdCl2 concentration inmethanol solution. In this way the whole dynamic of the chemical reaction from the minimumactivation energy is analyzed. Activated CdTe layers have been analyzed by means of X-ray diffraction and atomic forcemicroscopy. Finished deviceswith efficiencies from 8% for the low temperature annealing up to more than 14% for the high temperature ones have been thoroughly analyzed by current–voltage, capacitance–voltage and drive-level capacitance profiling techniques. The best performance has been achieved with an annealing temperature of 395 °C.
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