ZnO and ZnMgO growth on a-plane sapphire by molecular beam epitaxy

Ogata, Kenichi; Koike, Kazuto; Tanite, T.; Komuro, T.; Feng, Yan; Sasa, Shigehiko; Inoue, M.; Yano, Mitsuaki

doi:10.1016/s0022-0248(02)02277-7

Cited by 93 publications

(43 citation statements)

References 20 publications

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“…As previously reported [23], RHEED patterns with (1×1) reconstruction during the growth suggested that ZnO surface was O-polarity with O termination. Also observed bright and sharp streaky RHEED patterns indicated a flat surface, which agreed with 0.4 nm of RMS value in AFM measurement.…”

Section: Resultssupporting

confidence: 82%

Characterization of undoped ZnO layers grown by molecular beam epitaxy towards biosensing devices

Ogata¹,

Komuro²,

Hama³

et al. 2004

Physica Status Solidi (b)

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Undoped ZnO layers grown by molecular beam epitaxy (MBE) were investigated aiming at biosensing devices based on organic/inorganic hybrid structures. Clear observation of free exciton emission in low temperature photoluminescence (PL) spectra and electron mobility as high as 114 cm 2 /Vs at room temperature indicate that the quality of the ZnO layers is applicable for biosensors. Surface bonding of the ZnO the layers, which is one of the key issues for hybridization, was examined by means of xray photoelectron spectroscopy (XPS). The XPS spectra of O 1s revealed that formation and desorption of hydroxyl (OH) bonds can be controlled by air exposure and thermal treatments. , establishment of hybridization between biofunctionalized molecules and inorganic semiconductor systems is of high importance. Until now, Si-based FETs are mainly utilized for them, however, compound semiconductors should be another candidates. In termes of fabrication of hybridized structures, their controllability of bandgap energies and lattice constants, which resulted in realization of laser diodes and high electron mobility transistors (HEMTs), would possess several potential. Among lots of compounds, i.e., numerous combinations of elements, we have chosen zinc oxide (ZnO) based semiconductors as materials for EnFET and biochemical sensors from the following reasons.One of the advantages of ZnO is expected to easily form direct bonding between organic molecules and the oxide surface. In case of non-oxide compounds, surface cleaning is necessary for precise bonding control, which can be realized by the removal of unintentionally formed amorphous oxide layer at the surface, while oxide surfaces are free from that. Considering that direct binding of biofunctional molecules on insulating gate layers in FETs is preferable for signal processing, availability of crystalline insulating layers of oxides is crucial for hybridization. Also it is expected that the techniques of selfassembled monolayer formation using organothiols on gold [3] would be applicable on oxide surfaces by the reaction between cation in oxide and S in molecules. In addition, multi-functionality of ZnO, such as large bandgap energy of 3.3eV for transparent electronics [4] and piezoelectricity for actuator [5], would be interesting for hybridization devices. From the viewpoint of biomedical applications, less hazardousness of oxides has attracted a great deal of attention, where other compound semiconductors cannot work.Recent progress on epitaxial growth of ZnO based semiconductors has been performed by molecular beam epitaxy (MBE) [6,7], pulsed laser deposition (PLD) [8,9] and metalorganic vapor phase epitaxy

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Section: Resultssupporting

confidence: 82%

Characterization of undoped ZnO layers grown by molecular beam epitaxy towards biosensing devices

Ogata¹,

Komuro²,

Hama³

et al. 2004

Physica Status Solidi (b)

Self Cite

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“…It can be seen that the lattice parameters a and c decrease with higher Mg content in the film, although especially for lattice parameter a the decrease is very small. This is in accordance with results of Ohtomo et al [3] (PLD deposition) and Ogata et al [9] (MBE deposition) who reported a decrease in lattice parameter c, while for Mg contents \ 10% lattice parameter a remains practically constant. In summary, XRD spectra confirmed the incorporation of small amounts of Mg into the ZnO lattice.…”

Section: Mg Incorporation Into the Zno Latticesupporting

confidence: 93%

Mg-doped ZnO films prepared by chemical bath deposition

et al. 2018

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A simple, low-temperature route for the chemical bath deposition of Mg-doped ZnO films, based on low-cost, abundant and non-toxic materials was developed. The film growth mechanism, the resulting morphology and texture were investigated in detail by scanning electron microscopy and X-ray diffraction measurements. It was found that substantial film growth is only possible in a narrow solution pH window due to the Zn(OH) 2 supersaturation as driving force for the film deposition. Different amounts of Mg in the solution cause distinct (0001), (10 10) or (10 11) ZnO crystal textures. Speciation modelling helped to understand the solution chemistry and explain the occurrence of different textures by face-selective adsorption of Mg species onto specific ZnO faces. The amount of incorporated Mg into the ZnO lattice, determined by inductively coupled plasma atomic emission spectroscopy, was limited to 2.1 mol%. Optical band gaps, calculated from transmittance spectra, showed an increase with higher amounts of incorporated Mg and ranged between 3.41 and 3.55 eV.

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“…Several techniques have been used to prepare ZnO films such as pulsed laser deposition (PLD) [1], molecular beam epitaxy (MBE) [2], DC magnetron sputtering [3], metal organic chemical vapour deposition (MOCVD) [4,5], spray pyrolysis [6,7], hybrid beam deposition (HBD) [8] and Sol-Gel technique [9,10].…”

Section: Introductionmentioning

confidence: 99%

Optical and structural characterisation of zinc oxide thin films prepared by sol-gel process

Сринивасан

Kumar²

2006

Cryst. Res. Technol.

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Zinc oxide thin films have been prepared on different substrates by the sol-gel method using 2-methoxyethanol solution of zinc acetate dihydrate stabilized by monoethanolamine. The photoluminescence spectra of the films show the band-edge and sub-band transitions. The intensity of the band edge emission peak increases, while the intensity of the deep level emission peak decreases in the films coated on sapphire substrate. Transmittance spectra show that the films are transparent beyond 400 nm. The structural property of the films has been evaluated using X-ray diffraction. The X-ray peak intensity of the film (002) grown on sapphire substrate is higher than the films grown on glass and quartz substrates. The AFM images show improvement in the surface of the annealed films as compared to the as-grown ZnO films coated on sapphire substrates.

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ZnO and ZnMgO growth on a-plane sapphire by molecular beam epitaxy

Cited by 93 publications

References 20 publications

Characterization of undoped ZnO layers grown by molecular beam epitaxy towards biosensing devices

Characterization of undoped ZnO layers grown by molecular beam epitaxy towards biosensing devices

Mg-doped ZnO films prepared by chemical bath deposition

Optical and structural characterisation of zinc oxide thin films prepared by sol-gel process

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