Title :
Cd1-xZnxTe solar cells with 1.6 eV band gap
Author :
McCandless, Brian E. ; Birkmire, Robert W.
Author_Institution :
Inst. of Energy Conversion, Delaware Univ., Newark, DE, USA
Abstract :
A pathway for fabricating high efficiency thin-film Cd1-xZnxTe solar cells with band gap ∼1.6 eV is demonstrated. Using successful CdTe/CdS thin film solar cell processing as a starting point, obtaining high efficiency Cd1-xZnxTe/CdS cells with the desired Zn content is accomplished by managing Zn loss mechanisms during post-deposition treatments. Specifically, treatment in CdCI2 removes Zn via chemical exchange while O2 promotes ZnO formation. Interdiffusion at the Cd1-xZnxTe-CdS interface converts the CdS film to Cd1-xZnxS. Cells with >11% efficiency at x = 0.05 were obtained using vapor transport deposited Cd1-xZnxTe treated in ZnCl2 vapor at low O2 ambient concentration. Cells with ITO contacts with >70% sub band gap transmission are demonstrated.
Keywords :
II-VI semiconductors; cadmium compounds; chemical exchanges; chemical interdiffusion; energy gap; semiconductor thin films; solar cells; thin film devices; vapour deposited coatings; vapour deposition; zinc compounds; Cd1-xZnxS; Cd1-xZnxTe solar cells; Cd1-xZnxTe-CdS; Cd1-xZnxTe-CdS interface; Cd1-xZnxTe/CdS cells; CdCI2 treatment; CdCl2; CdTe/CdS thin film solar cell processing; ITO contacts; Zn loss mechanism; ZnO; ZnO formation; ambient concentration; band gap; chemical exchange; high efficiency thin-film solar cells; interdiffusion; post-deposition treatment; subband gap transmission; vapor transport deposited Cd1-xZnxTe; Absorption; Fabrication; Lattices; Optical films; Photonic band gap; Photovoltaic cells; Surface treatment; Tellurium; X-ray scattering; Zinc compounds;
Conference_Titel :
Photovoltaic Specialists Conference, 2005. Conference Record of the Thirty-first IEEE
Print_ISBN :
0-7803-8707-4
DOI :
10.1109/PVSC.2005.1488153
