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High‐surface‐quality nanocrystalline InN layers deposited on GaN templates by RF sputtering
Author(s) -
ValduezaFelip Sirona,
Naranjo Fernando B.,
GonzálezHerráez Miguel,
Lahourcade Lise,
Monroy Eva,
Fernández Susana
Publication year - 2011
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200925636
Subject(s) - wurtzite crystal structure , materials science , sputtering , substrate (aquarium) , indium nitride , nanocrystalline material , surface roughness , sapphire , band gap , optoelectronics , thin film , deposition (geology) , wide bandgap semiconductor , nitride , rf power amplifier , optics , nanotechnology , zinc , composite material , layer (electronics) , metallurgy , cmos , amplifier , laser , oceanography , biology , paleontology , physics , sediment , geology
Abstract We report a detailed study of the effect of deposition parameters on optical, structural, and morphological properties of InN films grown by reactive radio‐frequency (RF) sputtering on GaN‐on‐sapphire templates in a pure nitrogen atmosphere. Deposition parameters under study are substrate temperature, RF power, and sputtering pressure. Wurtzite crystallographic structure with c ‐axis preferred growth orientation is confirmed by X‐ray diffraction measurements. For the optimized deposition conditions, namely at a substrate temperature of 450 °C and RF power of 30 W, InN films present a root‐mean‐square surface roughness as low as ∼0.4 nm, comparable to the underlying substrate. The apparent optical bandgap is estimated at 720 nm (1.7 eV) in all cases. However, the InN absorption band tail is strongly influenced by the sputtering pressure due to a change in the species of the plasma.