Abstract
This report summarizes the development and evaluation of higher-bandgap absorbers in the CIS alloy system. The major effort focused on exploring suitable absorbers with significant sulfur alloying in collaboration with Shafarman's group at the Institute of Energy Conversion. Three series of samples were examined; first, a series of quaternary CuIn(SeS)2-based devices without Ga; second, a seriesof devices with pentenary Cu(InGa)(SeS)2 absorbers in which the Se-to-S and In-to-Ga ratios were chosen to keep the bandgap nearly constant, near 1.52 eV. Third, based on the most-promising samples in those two series, we examined a series of devices with pentenary Cu(InGa)(SeS)2 absorbers with roughly 25 at.% S/(Se+S) ratios and varying Ga fractions. We also characterized electronic propertiesof several wide-bandgap CuGaSe2 devices from both IEC and NREL. The electronic properties of these absorbers were examined using admittance spectroscopy, drive-level capacitance profiling, transient photocapacitance, and transient photocurrent optical spectroscopies. The sample devices whose absorbers had Ga fraction below 40 at.% and S fractions above 20 at.% but below 40% exhibited the bestelectronic properties and device performance.
Original language | American English |
---|---|
Number of pages | 76 |
State | Published - 2008 |
Bibliographical note
Work performed by University of Oregon, Eugene, OregonNREL Publication Number
- NREL/SR-520-43909
Keywords
- admittance spectroscopy
- chalcopyrites
- CIGS
- CIS alloys
- devices
- drive-level capacitance profiling
- electronic properties
- high bandgap
- PV
- thin films
- transient photocapacitance (TPC)