A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITE<font>ZnO</font>BY FIRST PRINCIPLES

Shi, Li; Shuang, Cheng; Li, Rong Bing; Kang, Li; Jin, Jian; Li, Ming Biao; Xu, Cui Yan

doi:10.1142/s0217984909020540

Cited by 7 publications

(4 citation statements)

References 35 publications

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“…This a-axis compressive strain may also be one of the reasons resulting in the UV enhancement, which is consistent with the work of Yang et al [24]. Besides, Li et al reported based on their calculation that the decrease of bandgap of ZnO along uniaxial a-axis compressive strain is attributed to the variation of hybridization of atomic orbits [25]. Thus this compressive strain observed after low energy irradiation is likely one of reasons that causes the red shift of the UV emission, as shown in Fig.…”

Section: Resultssupporting

confidence: 88%

Significant enhancement of UV emission in ZnO nanorods subject to Ga+ ion beam irradiation

Yadian

Chen

et al. 2015

Nano Res.

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published as an ASAP article. Please note that technical editing may introduce minor changes to the manuscript text and/or graphics which may affect the content, and all legal disclaimers that apply to the journal pertain. In no event shall TUP be held responsible for errors or consequences arising from the use of any information contained in these "Just Accepted" manuscripts. To cite this manuscript please use its Digital Object Identifier (DOI®), which is identical for all formats of publication.

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Section: Resultssupporting

confidence: 88%

Significant enhancement of UV emission in ZnO nanorods subject to Ga+ ion beam irradiation

Yadian

Chen

et al. 2015

Nano Res.

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“…Shi et al have reported that, in an under-strain ZnO supercell, the bottom of the conduction band is dominated by the Zn 4s level and the O 2p level is determinative for the top of the valence band. Based on the density functional theory and the plane-wave pseudopotential method, they found that when c-axial strain varies from tensile to compressive, the O 2p level shifts to a lower energy while Zn 4s shifts oppositely; therefore, the band gap of ZnO increases linearly with decreasing c [25]. Our experimental result on individual ZnO nanowires provides strong evidence that the strain can bring about the linear variation in the band gap of ZnO, which is well consistent with the theoretical prediction.…”

Section: Resultsmentioning

confidence: 99%

Probing the strain effect on near band edge emission of a curved ZnO nanowire via spatially resolved cathodoluminescence

Xue

Pan²,

et al. 2010

Nanotechnology

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Curved ZnO nanowires were deliberately prepared on a Si substrate and the strain effect on their near band edge (NBE) emission was investigated by spatially resolved cathodoluminescence (CL). By moving the electron beam step-by-step across individual curved nanowires and acquiring the CL spectra simultaneously, we found that the NBE emissions from the inner region of the curved nanowires with compressive strain show blueshift, while those from the outer region with tensile strain show redshift. Both the strains have been estimated from the local curvature by a geometrical model and have been further examined by high-resolution transmission electron microscopy. A nearly linear relation between the strain and the peak energy shift in NBE emission was obtained. The result indicates that the optical band gap of ZnO nanowire is quite sensitive to and can be readily modulated by the induced strain via simply curving the nanowire, which has potential applications for designing new optical-electromechanical (OEM) and flexible optoelectronic nanodevices.

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“…The peak positions of the four emission bands did not exhibit any appreciable shift under straining (Figure c), but they did have obvious blue shift as the applied bias voltage was increased (see Section B in Supporting Information). It is known that the bandgap of ZnO decreases under compressive a- axis strain, − while the bandgap of GaN also decreases under compressive c -axis strain. , In this case, the peak position should have a red shift under compressive strain. On the other hand, the emission centers of the n-ZnO/p-GaN LED have blue shift with the increase of injection current due to the band renormalization, band filling at high current and/or the increased kinetic energies of electrons and holes .…”

mentioning

confidence: 99%

Enhancing Light Emission of ZnO Microwire-Based Diodes by Piezo-Phototronic Effect

et al. 2011

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Light emission from semiconductors depends not only on the efficiency of carrier injection and recombination but also extraction efficiency. For ultraviolet emission from high band gap materials such as ZnO, nanowires have higher extraction efficiencies than thin films, but conventional approaches for creating a p-n diode result in low efficiency. We exploited the noncentral symmetric nature of n-type ZnO nanowire/p-type GaN substrate to create a piezoelectric potential within the nanowire by applying stress. Because of the polarization of ions in a crystal that has noncentral symmetry, a piezoelectric potential (piezopotential) is created in the crystal under stress. The piezopotential acts as a "gate" voltage to tune the charge transport and enhance carrier injection, which is called the piezo-phototronic effect. We propose that band modification traps free carriers at the interface region in a channel created by the local piezoelectric charges. The emission intensity and injection current at a fixed applied voltage have been enhanced by a factor of 17 and 4, respectively, after applying a 0.093% compressive strain and improved conversion efficiency by a factor of 4.25. This huge enhanced performance is suggested arising from an effective increase in the local "biased voltage" as a result of the band modification caused by piezopotential and the trapping of holes at the interface region in a channel created by the local piezoelectric charges near the interface. Our study can be extended from ultraviolet range to visible range for a variety of optoelectronic devices that are important for today's safe, green, and renewable energy technology.

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A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITEZnOBY FIRST PRINCIPLES

Cited by 7 publications

References 35 publications

Significant enhancement of UV emission in ZnO nanorods subject to Ga+ ion beam irradiation

Significant enhancement of UV emission in ZnO nanorods subject to Ga+ ion beam irradiation

Probing the strain effect on near band edge emission of a curved ZnO nanowire via spatially resolved cathodoluminescence

Enhancing Light Emission of ZnO Microwire-Based Diodes by Piezo-Phototronic Effect

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