Title :
Investigation of buffer layer process on CIGS solar cells by dual beam optical modulation technique
Author :
Huang, C.H. ; Li, Sheng S. ; Stanbery, B.J. ; Chang, C.H. ; Anderson, T.J.
Author_Institution :
Dept. of Electr. & Comput. Eng., Florida Univ., Gainesville, FL, USA
fDate :
29 Sep-3 Oct 1997
Abstract :
A contactless, nondestructive reflection mode dual beam optical modulation (DBOM) technique has been employed to investigate the effects of different CdS buffer layer processings (i.e., CBD, MOCVD, and sputtering) on the properties of CIS/CIGS films. The results show a significant increase in the DBOM signal (ΔI/I) which is attributed to change of the free carrier absorption and of excess carrier lifetime in the absorber layer, after the buffer layer processing. In order to explain the observed DBOM results, an analytical model for the CIGS P-N junction cell is derived which contains the functional dependence of ΔI/I on the surface/interface recombination velocities, excess carrier lifetimes, diffusion length and depletion layer width in the CIS or CIGS cells. A detailed comparison of the DBOM data versus different processing is presented in this paper
Keywords :
CVD coatings; II-VI semiconductors; cadmium compounds; carrier lifetime; chemical vapour deposition; copper compounds; p-n junctions; semiconductor thin films; solar cells; sputtered coatings; sputtering; surface recombination; ternary semiconductors; CIGS solar cells; CdS buffer layer processing; CdS-Cu(InGa)Se2; Cu(In,Ga)Se2 solar cells; MOCVD; absorber layer; buffer layer process; buffer layer processing; chemical bath deposition; depletion layer width; diffusion length; dual beam optical modulation technique; excess carrier lifetime; excess carrier lifetimes; free carrier absorption; nondestructive reflection mode DBOM; sputtering; surface/interface recombination velocities; Buffer layers; Charge carrier lifetime; Computational Intelligence Society; MOCVD; Optical beams; Optical films; Optical modulation; Optical reflection; Photovoltaic cells; Sputtering;
Conference_Titel :
Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3767-0
DOI :
10.1109/PVSC.1997.654114
