Catalyst-free chemical vapor deposition route to InN nanowires and their cathodoluminescence properties

Effects of NH3 Flow Rate on the Growth Mechanism and Optical Properties of InN Crystallites Fabricated by Chemical Vapor Deposition

“…But, the O impurities and defects in the nanowires and microcrystallites, which were confirmed by XPS analysis, should be considered as plausible factors that can lead to larger band gap energy. As indicated above, for the InN nanowires, the emission peak located at ∼665 nm may be mainly attributed to the O impurities . And the broad half-width of the PL peak is principally the influence of the thermal excitations together with the broad size distribution of the nanowires .…”

“…As compared with the InN nanowires, the intensity of the emission band of the microcrystallites is slightly strengthened, while the maximum of the emission band exhibits a significant blue-shifting from 665 to 570 nm. In recent years, reports about the optical band gap of InN have provoked fierce debate, for they showed different values from 0.6 to 2.2 eV. ,,,, Currently, theoretical calculations and experimental results indicate that the intrinsic band gap of InN is ∼0.65 eV. − The PL properties of InN materials affected by their shape and size, as well as the synthetic process and parameters, have been widely reported. − The quantum confinement effect, oxygen impurities, strain effect, the defects including N antisite (N In ), In antisite (In N ), N vacancy (V N ), In vacancy (V In ), and a complex defect (N In +In N ), or the Moss–Burstein shift induced by high electron concentrations of the InN nanostructures have been proposed as possible reasons for an increased band gap of InN. ,,,,− Recent reports showed that the major reason for the larger band gap of InN is the influence of oxygen inclusion. − Davydov et al showed that an InN sample containing ∼20% of oxygen has a band gap in the region of 1.8–2.1 eV . And Yoshimoto et al reported that, with the values of oxygen molar fractions in a series of polycrystalline InN layers changed from 1% to 6%, the associated band gap increased from 1.55 to 2.27 eV .…”

“…As indicated above, for the InN nanowires, the emission peak located at ∼665 nm may be mainly attributed to the O impurities. 47 And the broad halfwidth of the PL peak is principally the influence of the thermal excitations together with the broad size distribution of the nanowires. 45 As for the pyramid-shaped InN microcrystallites, the blue-shifting from 665 to 570 nm could not be simply attributed to the O impurities, for the difference of oxygen contents between the InN microcrystallites and nanowires are not significant.…”

Biotemplating fabrication, mechanical and electrical characterizations of NbC nanowire arrays from the bamboo substrate

“…This limits their applications in constructing NbC based nanocomposites and nano-devices. To date, various techniques including carbon nanotube confined reaction [18], chemical vapor deposition [19], carbon thermal reduction [20][21][22], and pyrolysis of polymeric precursors [23] have been developed for the preparation of 1D carbide nanostructures. In our recent studies, a facile and cost-effective biotemplating method has been developed to synthesize 1D TMC nanostructures [13,14,24].…”

Self-Catalyzed Growth of Vertically Aligned InN Nanorods by Metal–Organic Vapor Phase Epitaxy

“…A self-catalytic or a catalyst-free growth of nanorods instead of a foreign catalyst particle induced growth is preferred since no impurity material, which degenerates the optical properties, can be incorporated into the material . High morphological and structural quality of vertically aligned, self-catalyzed InAs and InP nanowires have been reported. , For self-catalyzed InN, there is only poor morphological and structural quality of random oriented nanowires. , …”