Defect level signatures in CuInSe2 by photocurrent and capacitance spectroscopy

Results of defect levels spectroscopy on epitaxial and polycrystalline CuInSe2 by photocurrent and capacitance methods are presented. Electronic parameters of defect levels found by photocurrent methods are compared with those obtained through the use of capacitance spectroscopy on CuInSe2 solar cells. In the discussion, we include the Meyer-Neldel plot as a method of differentiation between the levels in the case of parameter variation between samples and depending on measurement conditions. The levels common for all compounds from the Cu(In,Ga) Se-2 family are specified. The origin of the N1 and N2 defect levels frequently observed in the capacitance spectra of solar cells is discussed and the coincidence of the N2 level and the E4 bulk level is shown. (C) 2013 Elsevier B.V. All rights reserved.