title: Spatially Resolved Thermodynamics of the Partially Ionized Exciton Gas in GaAs.
abstract: We report on the observation of macroscopic free exciton photoluminescence (PL) rings that appear in spatially resolved PL images obtained on a high purity GaAs sample. We demonstrate that a spatial temperature gradient in the photocarrier system, which is due to nonresonant optical excitation, locally modifies the population balance between free excitons and the uncorrelated electron-hole plasma described by the Saha equation and accounts for the experimentally observed nontrivial PL profiles. The exciton ring formation is a particularly instructive manifestation of the spatially dependent thermodynamics of a partially ionized exciton gas in a bulk semiconductor.
authors.affiliation: Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bieker
authors.affiliation: Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Henn
authors.affiliation: Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kiessling
authors.affiliation: Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Ossau
authors.affiliation: Physikalisches Institut (EP3) der Universität Würzburg, 97074 Würzburg, Germany.
authors.forename: L W
authors.initials: LW
authors.lastname: Molenkamp