Defect characterization in ZnO layers grown by plasma-enhanced molecular-beam epitaxy on (0001) sapphire substrates

Vigué, F.; Vennéguès, P.; Vézian, S.; Laügt, M.; Faurie, J. P.

doi:10.1063/1.1384907

Cited by 109 publications

(44 citation statements)

References 17 publications

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“…Before growth, the substrate was annealed at 750 °C under vacuum ≈10 −9 Torr for 15 min, and subsequently exposed in oxygen plasma to make the surface of (0001) Al 2 O 3 O-terminated. [ 43 ] A designed four-step buffer layers [ 44 ] were deposited in sequence for reducing the mismatch between the epitaxial fi lms and the substrate. Then three samples with different Be source temperature (0, 1000, and 1025 °C) were grown at T sub = 500 °C.…”

Section: Fabrication Of N-doped Bezno Films and P-i-n Junctions On Samentioning

confidence: 99%

Beryllium‐Assisted p‐Type Doping for ZnO Homojunction Light‐Emitting Devices

Chen

Zhu

et al. 2016

Adv Funct Materials

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A key step in realization of a ZnO homojunction light-emitting diode is the effective p-type doping in ZnO:N. In this article, a feasible route is demonstrated to enhance hole doping in ZnO:N fi lms by the assistance of Beryllium. The newly synthesized p-type ZnO is applied in light-emitting devices. The corresponding p-i-n junction exhibits excellent diode characteristics, and strong near band edge ultraviolet emissions is also observed even at temperatures as high as 400 K under the injection of continuous current. The results represent a critical advance toward the development of high-effi ciency and stabilized p-type ZnO, which is also a desirable key step for future ZnO-based optoelectronic applications.

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Section: Fabrication Of N-doped Bezno Films and P-i-n Junctions On Samentioning

confidence: 99%

Beryllium‐Assisted p‐Type Doping for ZnO Homojunction Light‐Emitting Devices

Chen

Zhu

et al. 2016

Adv Funct Materials

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“…Several growth techniques, such as spray pyrolysis, sputtering, pulsed laser deposition (PLD), molecular beam epitaxy (MBE) and metal-organic chemical vapour deposition (MOCVD), have been extensively used for the deposition of ZnO films and most of this work has been extensively reviewed [1][2][3][4]. High-quality ZnO epilayers have usually been grown on crystalline substrates, such as sapphire by PLD [5][6][7], MBE [8][9][10] and MOCVD [11,12]. In recent years, there has been an increasing interest in the growth of ZnO epilayers by sputtering [13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

High optical quality ZnO epilayers grown on sapphire substrates by reactive magnetron sputtering of zinc target

Singh

Kumar

Ganguli

et al. 2008

Journal of Crystal Growth

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“…The (0001) 28 has been applied to determine the polarity ( Figure 4E), and the result indicates that the interior surface of the ring is (0001)-Zn and the exterior surface is (0001 h)-O. 29 Physically, if the surface charges are uncompensated during the growth, 30 the net dipole moment tends to diverge and the electrostatic energy increases.…”

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confidence: 99%

Spontaneous Polarization-Induced Nanohelixes, Nanosprings, and Nanorings of Piezoelectric Nanobelts

2003

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Growth of (0001) facet-dominated, free-standing, piezoelectric zinc oxide (ZnO) nanostructures is challenged by the divergence of the surface energy due to intrinsic polarization. By controlling growth kinetics, we show the success of growing nanobelt-based novel structures whose surfaces are dominated by the polarized ±(0001) facets. Owing to the positive and negative ionic charges on the zinc-and oxygen-terminated ±(0001) surfaces, respectively, a spontaneous polarization is induced across the nanobelt thickness. As a result, right-handed helical nanostructures and nanorings are formed by rolling up single-crystal nanobelts; this phenomenon is attributed to a consequence of minimizing the total energy contributed by spontaneous polarization and elasticity. The polar-surface-dominated ZnO nanobelts are likely to be an ideal system for understanding piezoelectricity and polarization-induced ferroelectricity at nanoscale; and they could have applications as onedimensional nanoscale sensors, transducers, and resonators.Zinc oxide (ZnO) is a versatile smart material that has key applications in catalysts, sensors, piezoelectric transducers, 1 transparent conductors, 2 and surface acoustic wave devices. 3The noncentral symmetry and the tetrahedral coordinated ZnO 4 unit in ZnO result in anisotropic piezoelectric properties. Structurally, the wurtzite structured ZnO crystal is described schematically as a number of alternating planes composed of four-fold coordinated O 2-and Zn 2+ ions, stacked alternatively along the c-axis. The oppositely charged ions produce positively charged (0001)-Zn and negatively charged (0001 h)-O polar surfaces, resulting in a normal dipole moment and spontaneous polarization as well as a divergence in surface energy. To maintain a stable structure, the polar surfaces generally have facets or exhibit massive surface reconstructions, but ZnO ( (0001) is an exception, which is atomically flat, stable, and without reconstruction. 4,5 Understanding the superior stability of the ZnO ( (0001) polar surfaces is a forefront research in today's surface physics. 6-9Nanowire-and nanotube-based materials have been demonstrated as building blocks for nanocircuits, nanosystems, 10-14 and nanooptoelectronics, 15 and they have been fabricated for a wide range of materials from metals, semiconductors, and oxides to polymers. 16 22 But these ZnO nanostructures grow along the c-axis, and the side surfaces are {011 h0} and {21 h 1 h0} due to their energies which are lower than that of (0001), resulting in vanishing dipole moment and much reduced piezoelectricity. The most desirable morphology to maximize the piezoelectric effect is to create nanostructures that preserve large area (0001) polar surfaces. 23,24 However, ZnO (0001) has a surface energy that diverges with sample size due to the surface polarization charge. Therefore, growth of (0001) surface-dominated free-standing nanostructures needs to oVercome the barrier of surface energy.In this paper, we report the free-standing ZnO nanobelts that g...

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Defect characterization in ZnO layers grown by plasma-enhanced molecular-beam epitaxy on (0001) sapphire substrates

Abstract: Articles you may be interested inElectron scattering mechanisms in GZO films grown on a-sapphire substrates by plasma-enhanced molecular beam epitaxy

Cited by 109 publications

References 17 publications

Beryllium‐Assisted p‐Type Doping for ZnO Homojunction Light‐Emitting Devices

Beryllium‐Assisted p‐Type Doping for ZnO Homojunction Light‐Emitting Devices

High optical quality ZnO epilayers grown on sapphire substrates by reactive magnetron sputtering of zinc target

Spontaneous Polarization-Induced Nanohelixes, Nanosprings, and Nanorings of Piezoelectric Nanobelts

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