title: Hopping conduction observed in thermal admittance spectroscopy.
abstract: We observe variable-range hopping conduction in thermal admittance spectroscopy and develop a method to evaluate the signal under this condition. As a relevant example of demonstration we employ Cu(In,Ga)(Se,S)2 thin-film solar cells and show that the fundamental N1 signal, which has been discussed for more than a decade in terms of minority carrier traps, does not display trap parameters, but is generated by the freezing-out of carrier mobility with decreasing temperature when hopping conduction prevails. This effect offers a new approach to carrier hopping and to semiconductors suffering from small mobility.
authors.affiliation: Friedrich-Schiller-Universität Jena, Physikalisch-Astronomische Fakultät, Institut für Festkörperphysik, Max-Wien-Platz 1, D-07743 Jena, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Reislöhner
authors.forename: H
authors.initials: H
authors.lastname: Metzner
authors.forename: C
authors.initials: C
authors.lastname: Ronning