abstract
Thin films and p-n junctions for solar cells based on the absorber materials Cu(In, Ga) Se-2 and Cu2ZnSnS4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu(+) state at the heterojunction interface as well as at the surface of the Cu(In, Ga)Se-2 film. This reduction is attributed to a reduced bonding reaction of the muon in the absorber defect layer at its surface. In addition, the activation energies for the conversion from a muon in an atomiclike configuration to a anion-bound position are determined from temperature-dependence measurements. It is concluded that the muon probe provides a measurement of the effective surface defect layer width, both at the heterojunctions and at the films. The CIGS surface defect layer is crucial for solar-cell electrical performance and additional information can be used for further optimizations of the surface.
keywords
CHALCOPYRITE SEMICONDUCTORS; ELECTRONIC-PROPERTIES; HYDROGEN STATES; BUFFER LAYERS; CU(IN,GA)SE-2; CDS; EFFICIENCY; CUINSE2; FUTURE; FILMS
subject category
Materials Science
authors
Alberto, HV; Vilao, RC; Vieira, RBL; Gil, JM; Weidinger, A; Sousa, MG; Teixeira, JP; da Cunha, AF; Leitao, JP; Salome, PMP; Fernandes, PA; Torndahl, T; Prokscha, T; Suter, A; Salman, Z
our authors
Ricardo Vieira
Junior Researcheracknowledgements
We are grateful to the PSI machine and beamline groups whose outstanding efforts have made these experiments possible. This work was supported with funds from FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT-Fundacao para a Ciencia e Tecnologia under Projects No. PTDC/FIS/102722/2008 and No. UID/FIS/04564/2016.