title: Possible high absorptance and low emittance selective surface for high temperature solar thermal collectors.
abstract: Optical reflectivity measurements show that the reflectivity of Ge is dramatically reduced in the wavelength 0.3-1.4-microm range after high dose oxygen ion implantation. To explain such greatly reduced reflectivity, a model has been developed for the reflectivity of high dose oxygen implanted germanium. Our experimentally measured and calculated reflectivities show that, for a layered structure consisting of a Ge and GeO(2) mixture on Ge on GeO(2) on a Cu substrate, a low reflectivity of 0-10% in the solar spectrum is obtained, together with a high reflectivity approximately 100% in the 1.7-25-microm wavelength range. This is close to that of an ideal selective surface for solar energy thermal collectors operating at high temperatures from 300 to 500 degrees C.
authors.forename: Q C
authors.initials: QC
authors.lastname: Zhang
authors.forename: J C
authors.initials: JC
authors.lastname: Kelly
authors.forename: D R
authors.initials: DR
authors.lastname: Mills