Surface optical phonon and A1(LO) in ZnO submicron crystals probed by Raman scattering: Effects of morphology and dielectric coating

Liu, H. F.; Tripathy, S.; Hu, Guo‐Xiong; Gong, Hao

doi:10.1063/1.3087482

Cited by 29 publications

(28 citation statements)

References 27 publications

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“…Indeed, Raman spectra of "ZnO submicron crystals" presented in Ref. [6] are dominated by the LO phonon mode (in addition, the authors of this work used resonant excitation at 325 nm). Probably something similar happens when the ZnO thin films are rather heavily doped, whatever the type of impurity (n or p) is.…”

Section: Contributed Articlementioning

confidence: 98%

Raman study of doped‐ZnO thin films grown by rf sputtering

Cerqueira

Rolo

Viseu

et al. 2010

Phys. Status Solidi (c)

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A Raman spectroscopy study of doped versus undoped ZnO layers is presented. The layers were grown by RF magnetron sputtering and the doping with Al, Sb and Mn was achieved by ion implantation with subsequent annealing. First‐order Raman response measured under λ=488 nm excitation is discussed. It is shown that doping with any of the impurities used in this work produces a strong enhancement of the longitudinal optical (LO) phonon band, which is attributed to the intra‐band Fröhlich mechanism. In addition, doping with Mn results in an extra mode located at 530 cm‐1, tentatively attributed to a local vibrational mode of Mn substituting Zn in the lattice sites. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Contributed Articlementioning

confidence: 98%

Raman study of doped‐ZnO thin films grown by rf sputtering

Cerqueira

Rolo

Viseu

et al. 2010

Phys. Status Solidi (c)

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“…These surface passivations increase the vibration frequency of the surface optical (SO) mode, decrease the intensity of the longitudinal optical mode, i.e., A 1 (LO), and enhance the near-band-edge (NBE) photoluminescence (PL) of the ZnO crystallites (see Ref. [5] and the reference therein). On the other hand, to reduce the unintentional incorporated defects and active the p-type doping of ZnO, post-growth thermal annealing is generally needed, which also causes structural and optical evolutions for ZnO [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Because of the abundance of surface and near-surface defects, stable and rectifying metal contacts to ZnO also remain a challenge in device fabrications [3,4]. Dielectric coatings, such as SiO 2 and Si 3 N 4 , are found to passivate the surface states of ZnO submicron crystals [5], likely due to the saturation of the surface broken bonds. These surface passivations increase the vibration frequency of the surface optical (SO) mode, decrease the intensity of the longitudinal optical mode, i.e., A 1 (LO), and enhance the near-band-edge (NBE) photoluminescence (PL) of the ZnO crystallites (see Ref.…”

Section: Introductionmentioning

confidence: 99%

Evolution of resonant Raman scattering spectra of ZnO crystallites upon post-growth thermal annealing

Liu

Chua

et al. 2010

Journal of Crystal Growth

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“…The SO modes are solutions of the first equation of (2.34), and their frequencies are always in between those of TO and LO modes. The position of the SO mode depends on the dielectric constant of the surrounding medium [36]- [38]. The dispersion is also nanowire shape-sensitive [34].…”

Section: Surface Optical Modesmentioning

confidence: 99%

Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures

Filippov¹

2016

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Abstract.Low-dimensional semiconductor structures, such as one-dimensional nanowires (NWs) and zero-dimensional quantum dots (QDs), are materials with novel fundamental physical properties and a great potential for a wide range of nanoscale device applications. Here, especially promising are direct bandgap II-VI and III-V compounds and related alloys with a broad selection of compositions and band structures. For examples, NWs based on dilute nitride alloys, i.e. GaNAs and GaNP, provide both an optical active medium and well-shaped cavity and, therefore, can be used in a variety of advanced optoelectronic devices including intermediate band solar cells and efficient light-emitters. Self-assembled InAs QDs formed in the GaAs matrix are proposed as building blocks for entangled photon sources for quantum cryptography and quantum information processing as well as for spin light emitting devices. ZnO NWs can be utilized in a variety of applications including efficient UV lasers and gas sensors. In order to fully explore advantages of nanostructured materials, their electronic properties and lattice structure need to be comprehensively characterized and fully understood, which is not yet achieved in the case of aforementioned material systems. The research work presented this thesis addresses a selection of open issues via comprehensive optical characterization of individual nanostructures using micro-Raman (-Raman) and microphotoluminescence (-PL) spectroscopies.In paper 1 we study polarization properties of individual GaNP and GaP/GaNP core/shell NWs using polarization resolved µ-PL spectroscopy. Near band-edge emission in these structures is found to be strongly polarized (up to 60% at 150K) in the orthogonal direction to the NW axis, in spite of their zinc blende (ZB) structure. This polarization response, which is unusual for ZB NWs, is attributed to the local strain in the vicinity of the N-related centers participating in the radiative recombination and to their preferential alignment along the growth direction, presumably caused by the presence of planar defects. Our findings therefore show that defect engineering via alloying with nitrogen provides an additional degree of freedom to control the polarization anisotropy of III-V nanowires, advantageous for their applications as a nanoscale source of polarized light.Structural and optical properties of novel coaxial GaAs/Ga(N)As NWs grown on Si II substrates, were evaluated in papers 2-4. In paper 2 we show by using -Raman spectroscopy that, though nitrogen incorporation shortens a phonon correlation length, the GaNAs shell with [N]<0.6% has a low degree of alloy disorder and weak residual strain.Additionally, Raman scattering by the GaAs-like and GaN-like phonons is found to be enhanced when the excitation energy approaches the E + transition energy. This effect was attributed the involvement of intermediate states that were created by N-related clusters in proximity to the E + subband. Recombination processes in these structures were studied in paper 3 by ...

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Surface optical phonon and A1(LO) in ZnO submicron crystals probed by Raman scattering: Effects of morphology and dielectric coating

Cited by 29 publications

References 27 publications

Raman study of doped‐ZnO thin films grown by rf sputtering

Raman study of doped‐ZnO thin films grown by rf sputtering

Evolution of resonant Raman scattering spectra of ZnO crystallites upon post-growth thermal annealing

Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures

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