title: Reduced workfunction intermetallic seed layers allow growth of porous n-GaN and low resistivity, ohmic electron transport.
abstract: Porous GaN crystals have been successfully grown and electrically contacted simultaneously on Pt- and Au-coated silicon substrates as porous crystals and as porous layers. By the direct reaction of metallic Ga and NH(3) gas through chemical vapor deposition, intermetallic metal-Ga alloys form at the GaN-metal interface, allowing vapor-solid-solid seeding and subsequent growth of porous GaN. Current-voltage and capacitance-voltage measurements confirm that the intermetallic seed layers prevent interface oxidation and give a high-quality reduced workfunction contact that allows exceptionally low contact resistivities. Additionally, the simultaneous formation of a lower workfunction intermetallic permits ohmic electron transport to n-type GaN grown using high workfunction metals that best catalyze the formation of porous GaN layers and may be employed to seed and ohmically contact a range of III-N compounds and alloys for broadband absorption and emission.
authors.affiliation: Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA) and EMaS, Universitat Rovira i Virgili (URV), Marcellí Domingo s/n, E-43007 Spain.
authors.forename: Oleksandr V
authors.initials: OV
authors.lastname: Bilousov
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Carvajal
authors.forename: Dominique
authors.initials: D
authors.lastname: Drouin
authors.forename: Xavier
authors.initials: X
authors.lastname: Mateos
authors.forename: Francesc
authors.initials: F
authors.lastname: Díaz
authors.forename: Magdalena
authors.initials: M
authors.lastname: Aguiló
authors.forename: Colm
authors.initials: C
authors.lastname: O'Dwyer