title: Integration of ZnO microcrystals with tailored dimensions forming light emitting diodes and UV photovoltaic cells.
abstract: This article reports a new integration approach to produce arrays of ZnO microcrystals for optoelectronic and photovoltaic applications. Demonstrated applications are n-ZnO/p-GaN heterojunction LEDs and photovoltaic cells. The integration process uses an oxygen plasma treatment in combination with a photoresist pattern on magnesium doped GaN substrates to define a narrow sub-100 nm width nucleation region. Nucleation is followed by lateral epitaxial overgrowth producing single crystal disks of ZnO with desired size over 2 in. wafers. The process provides control over the dimensions (<1% STD) and the location (0.7% STD pitch variation) of the ZnO crystals. The quality of the patterned ZnO is high; the commonly observed defect related emission in the electroluminescence spectra is completely suppressed, and a single near-band-edge UV peak is observed.
authors.affiliation: University of Minnesota, Electrical Engineering Room 4-178, 200 Union Street SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Cole
authors.forename: Xinyu
authors.initials: X
authors.lastname: Wang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Knuesel
authors.forename: Heiko O
authors.initials: HO
authors.lastname: Jacobs
mesh_terms: D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008029:Lighting / Q000295:instrumentation* / Q000379:methods; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods; D012666:Semiconductors; D018511:Systems Integration; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D015034:Zinc Oxide / Q000737:chemistry* / Q000528:radiation effects
chemical_list: C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide