Title :
Stoichiometric effects in polycrystalline CdTe
Author :
Khan, Mahrukh ; Evani, V. ; Collins, Stephen ; Palekis, V. ; Bane, P. ; Bakhshi, S. ; Kendre, V. ; Vatavu, S. ; Morel, D. ; Ferekides, C.
Author_Institution :
Univ. of South Florida, Tampa, FL, USA
Abstract :
The effect of the vapor phase Cadmium (Cd) to Tellurium (Te) ratio on the electronic properties of CdTe films is being studied. The stoichiometry of CdTe films is being altered by varying the gas phase Cd/Te ratio during the Elemental Vapor Transport (EVT) deposition process. Resistivity-temperature measurements and solar cells made with polycrystalline EVT-CdTe suggest changes in the native cadmium vacancy (VCd) concentration and carrier lifetime. The findings are in good agreement with the recently updated defect levels using the HSE approximation. Photoluminescence (PL) analysis has also demonstrated variation in the formation of defect complexes with the Cd/Te ratio. 2-Photon TRPL lifetime measurements showed improved minority-carrier lifetime for CdCl2 treated samples deposited at low Cd/Te ratios.
Keywords :
II-VI semiconductors; cadmium compounds; carrier lifetime; electrical resistivity; minority carriers; photoluminescence; semiconductor thin films; solar cells; stoichiometry; vacancies (crystal); vapour deposition; wide band gap semiconductors; 2-photon TRPL lifetime; CdTe; defect complexes; defect levels; electronic properties; elemental vapor transport deposition; minority-carrier lifetime; native cadmium vacancy concentration; photoluminescence analysis; resistivity-temperature measurements; solar cells; stoichiometric effects; thin films; vapor phase; Cadmium; Heating; Indexes; Integrated circuits; Molecular beam epitaxial growth; Phase measurement; Radio frequency; cadmium compound; defect; doping; lifetime;
Conference_Titel :
Photovoltaic Specialist Conference (PVSC), 2014 IEEE 40th
Conference_Location :
Denver, CO
DOI :
10.1109/PVSC.2014.6925397
