Soft X-ray characterization of Zn1-xSnxOy electronic structure for thin film photovoltaics
2012 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 14, no 29, 10154-10159 p.Article in journal (Refereed) Published
Zinc tin oxide (Zn1-xSnxOy) has been proposed as an alternative buffer layer material to the toxic, and light narrow-bandgap CdS layer in CuIn1-x,GaxSe2 thin film solar cell modules. In this present study, synchrotron-based soft X-ray absorption and emission spectroscopies have been employed to probe the densities of states of intrinsic ZnO, Zn1-xSnxOy and SnOx thin films grown by atomic layer deposition. A distinct variation in the bandgap is observed with increasing Sn concentration, which has been confirmed independently by combined ellipsometry-reflectometry measurements. These data correlate directly to the open circuit potentials of corresponding solar cells, indicating that the buffer layer composition is associated with a modification of the band discontinuity at the CIGS interface. Resonantly excited emission spectra, which express the admixture of unoccupied O 2p with Zn 3d, 4s, and 4p states, reveal a strong suppression in the hybridization between the O 2p conduction band and the Zn 3d valence band with increasing Sn concentration.
Place, publisher, year, edition, pages
2012. Vol. 14, no 29, 10154-10159 p.
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject Engineering Science with specialization in Electronics
IdentifiersURN: urn:nbn:se:uu:diva-178156DOI: 10.1039/c2cp41394aISI: 000305965200011OAI: oai:DiVA.org:uu-178156DiVA: diva2:542143