Observation of Unintentionally Incorporated Nitrogen-Related Complexes in ZnO and GaN Nanowires

Soudi, Afsoon; Khan, Enamul; Dickinson, J. T.; Gu, Yi

doi:10.1021/nl803830n

Cited by 50 publications

(35 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The NWs used in this study were synthesized by the vapor-liquid-solid method on Si/SiO 2 substrates with Au colloids as the catalysts [27]. A mixture of ZnO (Alfa Aesar, 99.999%) and graphite (Alfa Aesar, 99.9995%) powders in a quartz boat was used as the Zn source.…”

Section: Methodsmentioning

confidence: 99%

Mechanical properties of ZnO nanowires under different loading modes

et al. 2010

View full text Add to dashboard Cite

A systematic experimental and theoretical investigation of the elastic and failure properties of ZnO nanowires (NWs) under different loading modes has been carried out. In situ scanning electron microscopy (SEM) tension and buckling tests on single ZnO NWs along the polar direction [0001] were conducted. Both tensile modulus (from tension) and bending modulus (from buckling) were found to increase as the NW diameter decreased from 80 to 20 nm. The bending modulus increased more rapidly than the tensile modulus, which demonstrates that the elasticity size effects in ZnO NWs are mainly due to surface stiffening. Two models based on continuum mechanics were able to fit the experimental data very well. The tension experiments showed that fracture strain and strength of ZnO NWs increased as the NW diameter decreased. The excellent resilience of ZnO NWs is advantageous for their applications in nanoscale actuation, sensing, and energy conversion.

show abstract

Section: Methodsmentioning

confidence: 99%

Mechanical properties of ZnO nanowires under different loading modes

et al. 2010

View full text Add to dashboard Cite

show abstract

“…For N 2 accommodated parallel to the basal plane and c-axis in ZnO, we calculated a vibrational frequency of x 0 = 2191 cm À1 and 2010 cm À1 , respectively. Compared with nitrogen molecules in vacuum or air, the vibrational mode exhibits a pronounced shift of up to 382 cm À1 to smaller wavenumbers (Table I) single-crystal ZnO, 28 ZnO, and GaN nanowires 29 showed a vibrational mode located at x 0 = 2306 cm À1 . While Friedrich and Nickel 28 suggested that its microscopic origin is linked to the presence of N-complexes, Soudi et al 29 claimed that this local vibrational mode is due to molecular nitrogen.…”

Section: The Molecular Orbitals Of N 2 and N 2 O Inmentioning

confidence: 99%

Properties of Nitrogen Molecules in ZnO

Nickel

Gluba

2010

Journal of Elec Materi

View full text Add to dashboard Cite

“…We are planning further studies on more efficient nanoparticle formation and doping and the effects of sample preparation and treatment. We also wish to investigate the plasmonic properties of the nanoparticles, nanostructures 6 of ZnO, and the interface between the two, all of which may have important applications in electronic and photonic devices. Steve Langford is a senior research associate focusing on probing mechanisms of laser/materials interactions, including defect production and both surface and bulk modification of transparent materials.…”

Section: Continued On Next Pagementioning

confidence: 99%

UV modification of zinc oxide

Khan¹

2009

SPIE Newsroom

View full text Add to dashboard Cite

Surface nanoparticles of zinc metal and bulk zinc and oxygen vacancies are produced by irradiation of single-crystal zinc oxide with 193nm excimer-laser light.In its hexagonal, wurtzite form, crystalline zinc oxide (ZnO) is a semiconductor with a direct, wide bandgap of 3.3eV and a range of actual and potential applications. It is often used for laser and light-emitting diodes in the blue to UV and its healthy quantum efficiency makes it a strong candidate for energyefficient lighting applications. In addition, ZnO can be used as a transparent conducting oxide coating and has potential for use in solar cells, LCDs, and flat-panel displays. When doped with manganese and cobalt, ZnO has possible applications in spintronics, a new technology that exploits the spin of electrons. However, a number of potential applications require robust p-type doping (which creates an abundance of positive-chargecarrying 'holes' in the semiconductor). This has yet to be achieved. 1-3 As a result, there is intense interest in understanding ZnO. 1 In principle, zinc vacancies can serve as p-type acceptors. In many transparent, wide-bandgap materials such as ZnO, nanosecond UV-laser radiation creates excitations that decay to yield defects, such as chlorine vacancies in sodium chloride (table salt), easily seen by visible coloration of the crystal. Yet similar treatments with nanosecond pulses do not normally produce lattice defects in ZnO. Rather, any resulting defects are soon annihilated by the rapid diffusion of zinc and oxygen atoms back to their original lattice positions. This accounts for the very high resistance of ZnO to radiation damage. 2,4 However, using a bigger hammer-6.3eV photons from an argon fluoride excimer laser-we have generated gray to black spots on ZnO 5 (see Figure 1). If this were a new type of color center, it would have to be called the 'smudge' defect. We used a variety of spectroscopic methods for further investigation and found that irradiation produces metallic zinc nanoparticles on the surface as well as zinc and oxygen vacancies in the bulk.We found that UV-visible absorption spectra of the surface material are remarkably similar to that of metal zinc films. Both x-ray and Auger photoelectron spectra indicate the presence of metallic zinc and selected-area x-ray diffraction showed peaks due to crystalline zinc metal. We used time-resolved quadrupole mass spectroscopy to identify intense emissions of atomic and molecular oxygen, O and O 2 , during irradiation in vacuum. Weaker emissions of atomic zinc were observed, consistent with metallic zinc being left behind. Most intriguingly, this surface zinc takes the form of nanoparticles, typically 10-20nm in diameter (see Figure 2). Careful transmission-electron-microscopy studies indicate that this zinc is confined strictly to the irradiated surface and, therefore, that the underlying bulk is free of nanoparticles. Metallic nanoparticles display interesting electronic and optical properties and usual production methods are complex compared to this example....

show abstract

Observation of Unintentionally Incorporated Nitrogen-Related Complexes in ZnO and GaN Nanowires

Cited by 50 publications

References 51 publications

Mechanical properties of ZnO nanowires under different loading modes

Mechanical properties of ZnO nanowires under different loading modes

Properties of Nitrogen Molecules in ZnO

UV modification of zinc oxide

Contact Info

Product

Resources

About