Title :
Study on deep defects in Cu(In,Ga)Se2 solar cells by photocapacitance spectroscopy
Author :
Sakurai, Takayasu ; Uehigashi, H. ; Islam, M.M. ; Miyazaki, T. ; Akimoto, K. ; Ishizuka, S. ; Sakurai, Kimio ; Yamada, A. ; Matsubara, K. ; Niki, S.
Author_Institution :
Institute of Applied Physics, University of Tsukuba, Ibaraki 305-8573, Japan
Abstract :
We study the electrical properties of deep defects in Cu(In,Ga)Se2 (CIGS) by transient photocapacitance (TPC) spectroscopy by varying the Ga concentration in CIGS. Regardless of the Ga concentration, the TPC spectra of CIGS thin-film solar cells at 100 K exhibited a defect level with an optical transition energy of about 0.8 eV. The TPC signals for defect level were quenched by increasing temperature. The activation energy of thermal quenching is estimated to be about 0.3 eV. The variation of the thermal and optical activation energies is caused by the distortions in the local defect configuration.
Keywords :
Capacitance measurement; Copper; Molecular beam epitaxial growth; Optical distortion; Optical films; Photovoltaic cells; Physics; Spectroscopy; Thermal quenching; Transistors;
Conference_Titel :
Photovoltaic Specialists Conference, 2008. PVSC '08. 33rd IEEE
Conference_Location :
San Diego, CA, USA
Print_ISBN :
978-1-4244-1640-0
Electronic_ISBN :
0160-8371
DOI :
10.1109/PVSC.2008.4922893
