Exciton photoluminescence of hexagonal ZnO

Butkhuzi, T.V.; Chelidze, T. G.; Georgobiani, A. N.; Jashiashvili, D. L.; Khulordava, T. G.; Tsekvava, B. E.

doi:10.1103/physrevb.58.10692

Cited by 65 publications

(42 citation statements)

References 4 publications

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“…Due to its high ionicity, ZnO is known to exhibit strong exciton-phonon coupling. The peak separation from the FX emission was seen to be 150 meV which is consistent with twice the reported value of 72 meV for the LO phonon energy of ZnO [4], and that of 75 meV experimentally observed on similar material produced by Eagle-Picher [5]. The relative position of the FX and FX-2LO peaks over the range of temperature from 225-300 K was also examined, where the lower end of the range was chosen to avoid convolution of free-and bound-exciton emission peaks.…”

Section: Resultssupporting

confidence: 76%

Chemomechanical Polishing Effects on the Room Temperature Photoluminescence of Bulk ZnO: Exciton-LO Phonon Interaction

Lucca

Hamby

Klopfstein

et al. 2002

phys. stat. sol. (b)

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A study of the effects of chemomechanical polishing on the room temperature photoluminescence of both polar faces of ZnO single crystals is presented. A distinct peak which we associate with second order exciton-phonon (FX-2LO) emission and which dominates the LO emission for both (0001) and (000 1 1) etched surfaces is observed. Chemomechanical polishing results in reduction of the distinct FX-2LO peak, and an increase in the relative importance of first order exciton-phonon (FX-1LO) emission. We attribute this to disorder introduced by the polishing process.Introduction The recent availability of high crystalline quality bulk ZnO presents new possibilities for short wavelength light emitters. Chemomechanical polishing is typically used in substrate preparation prior to epitaxial growth for creating flat surfaces with minimum roughness and subsurface damage. In this work, we examined the effects of chemomechanical polishing on the room temperature (RT) photoluminescence (PL) of both polar faces of undoped ZnO single crystals.

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Section: Resultssupporting

confidence: 76%

Chemomechanical Polishing Effects on the Room Temperature Photoluminescence of Bulk ZnO: Exciton-LO Phonon Interaction

Lucca

Hamby

Klopfstein

et al. 2002

phys. stat. sol. (b)

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“…The energy difference between the peak and the hump in these systems roughly reflects energies of many-body interactions such as e-ph and electron-plasmon interactions [26]. In the case of the present ZnO system, the energy difference between the peak and the hump is around 70 meV, which is close to the energy of the longitudinal optical (LO) phonon of the ZnO crystal ( ω ph = 72 meV [27]). Thus, we speculate that the e-ph coupling should be responsible for the multiple-component structures; namely, the peak and the hump originate from the 2DQP states and a phonon satellite (a 2D e-ph satellite), respectively.…”

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confidence: 83%

“…The same lineshape analysis was carried out for the EDCs of the 2DQP band on the H-dosed ZnO(1010) surface, and the results with ω ph = 72 meV for the ZnO surface [27] are shown in Figs. 4(a) and 4(b).…”

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confidence: 98%

Phonon-dressed two-dimensional carriers on the ZnO surface

et al. 2016

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Two-dimensional (2D) metallic states formed on the ZnO(1010) surface by hydrogen adsorption have been investigated using angle-resolved photoelectron spectroscopy (ARPES). The observed metallic state is characterized by a peak-dip-hump structure at just below the Fermi level and a long tail structure extending up to 600 meV in binding energy. The peak and hump positions are separated by about 70 meV, a value close to the excitation energy of longitudinal optical (LO) phonons. Spectral functions formulated on the basis of the 2D electron-phonon coupling well reproduce the ARPES intensity distribution of the metallic states. This spectral analysis suggests that the 2D electrons accumulated on the ZnO surface couple to the LO phonons and that this coupling is the origin of the anomalous long tail. Our results indicate that the 2D electrons at the ZnO surface are described as the electron liquid model. A characteristic difference among the 2DESs with different orbital character is the many-body effects of the electronic system such as electron-phonon (e-ph) and electron-plasmon interactions. Recent ARPES studies have reported that the many-body interactions in the 2DESs on SrTiO 3 (001) are inevitable and the 2DESs should be described in terms of the electron liquid [10,13]. In these 2DESs, the tails that accompany the two-dimensional (2D) metallic band have been attributed to energy loss structures by the e-ph coupling interaction. A similar enhanced spectral weight has also been observed for the 2DESs on anatase TiO 2 surfaces [16]. On the other hand, no such anomalous spectral weight has been reported for the s-orbital derived 2D metallic bands on ZnO(1010) [3][4][5], ZnO(0001) [2,3], In 2 O 3 (111) [6], and CdO(001) surfaces [7,8]. This systematic difference implies that the e-ph coupling strength might be weaker for the s electrons than the d electrons. However, this difference is against the theoretical predictions [17] that the orbital character should have little effect on the e-ph coupling. Therefore, the solution of this discrepancy is one of the challenging subjects for the 2DESs on oxide surfaces.In the present study, the electronic structure of the 2DES developed on the H-dosed ZnO(1010) surface was examined by ARPES. The detailed measurements have allowed us to successfully extract 2D quasiparticle (2DQP) bands and the e-ph satellites from the measured broad band, which has been regarded as a single metallic band in the previous studies [2][3][4][5]18]. The spectral analysis reveals the e-ph coupling strength of α = 0.30 − 0.34, indicating a sufficient e-ph coupling in the 2DES on the ZnO(1010) surface.Single-crystal ZnO(1010) was cleaned in situ by wellestablished procedures [19, 20]. H 2 molecules were cracked by hot tungsten filaments and dosed on the surface at room temperature. By these procedures, surfacelocalized O 2p dangling-bond state is suppressed and a 2DES is induced at the surface [5]. The ARPES measurements were performed at BL-1 of a compact electronstorage ring (HiSOR) at Hiroshima Uni...

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“…The half-widths of the two D 0 X peaks are a few meV (3~4 meV). The 3.327 eV emission band is observed and is attributed to two-electron satellites (TES) [12]. A peak of 3.264 eV also observed weakly and attributed to donoracceptor-pair (DAP), which implies that the ZnO film is high-quality, too [13].…”

Section: Contributedmentioning

confidence: 93%

Fabrication and photoluminescence properties of high‐quality ZnO film grown by solution‐vaporizing MOCVD

Ohshima

Abe

et al. 2013

Phys. Status Solidi C

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High‐quality ZnO film has been successfully grown on 2 inch c‐plane sapphire substrate using Zn(DPM)2 and O2 as zinc and oxygen sources by a solution‐vaporizing MOCVD technique. All films deposited at the substrate temperatures of 680 ∼ 760 °C were preferentially oriented along the (0001) direction and increasing the substrate temperature the full width at half maximum (FWHM) of the (0002) peak was decreased, as the crystallinity is improved. At the optimized substrate temperature of 740 °C the film showed the smallest FWHM was about 240 arcsec with the smoothest surface. In photoluminescence analysis of the film deposited at 740 °C, exciton emissions bound to the neutral donor (D0X) and two‐electron satellites (TES) emission dominated the edge emission region while phonon replicas of D0X and TES dominated the lower energy region with a weakly donor‐acceptor‐pair emission. Further, a comparatively negligible defect luminescence was observed, which indicated high‐quality ZnO film obtained. With increased temperature, the PL intensity of D0X and TES emissions decreased, which peaks shifts to the lower energy side, while the intensity of the free exciton emission increases and finally dominates the spectrum at room temperature. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Exciton photoluminescence of hexagonal ZnO

Cited by 65 publications

References 4 publications

Chemomechanical Polishing Effects on the Room Temperature Photoluminescence of Bulk ZnO: Exciton-LO Phonon Interaction

Chemomechanical Polishing Effects on the Room Temperature Photoluminescence of Bulk ZnO: Exciton-LO Phonon Interaction

Phonon-dressed two-dimensional carriers on the ZnO surface

Fabrication and photoluminescence properties of high‐quality ZnO film grown by solution‐vaporizing MOCVD

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