Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy

Han, Shuangfeng; Hong, Soon–Ku; Lee, J.W.; Lee, J.Y.; Song, Jang Ho; Nam, Yoon Sung; Chang, S. K.; Minegishi, Tsutomu; Yao, Takafumi

doi:10.1016/j.jcrysgro.2007.09.025

Cited by 94 publications

(66 citation statements)

References 18 publications

(21 reference statements)

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“…Figure 3 shows PL spectra of near-band-edge emission from ZnO (1120) films grown at N 2 = 0.0 to 8.0 sccm measured at 5 K. Figure 4 shows temperature dependence of PL spectra of the ZnO (1120) film grown at N 2 = 0.0 sccm. PL emissions at 3.378 eV, 3.368 eV and 3.308 eV were observed in all samples measured at 5 K. It has been reported that free-exciton emission (FE) was observed at around 3.378 eV from ZnO (0001) films [12] and that FEs were observed at 3.385 eV and 3.386 eV from strained non-polar ZnO (1120) films grown on single crystal sapphire ( ) 0112 substrates [5,6]. The peak at 3.368 eV was assigned to ionized-donor-bound exciton (D + X) and 3.362 eV was assigned to neutral-donor-bound exciton (D 0 X) on ZnO (0001) films [13,14].…”

Section: Contributedmentioning

confidence: 72%

“…with about 1 nm of root mean square (RMS) roughness, independently of N 2 gas flow rate. In a previous study on heteroepitaxial ZnO (1120) films grown on sapphire ( ) 0112 substrates by plasma-assisted molecular-beam epitaxy [6], the RMS roughnesses were 4.4 nm and the surfaces of the films had nanoscale stripes running in the ZnO <0001> direction [6]. The use of ZnO (1120) substrates and growth rate control were effective for obtaining ZnO (1120) films with smooth surfaces.…”

Section: Contributedmentioning

confidence: 96%

“…There have been few studies on non-polar ZnO (1120) films, and those films have been grown on single crystal sapphire (01 12) substrates with large mismatch of lattice constants and thermal expansion coefficient [4][5][6]. Single crystal ZnO (1120) substrates were useful for preparation high-quality non-polar ZnO (1120) films because of the absence of mismatches.…”

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confidence: 99%

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Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Abe

Nakagawa

Chiba

et al. 2009

Phys. Status Solidi (c)

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Non‐doped ZnO films and nitrogen‐doped ZnO films (ZnO:N films) were grown epitaxially on non‐polar single crystal ZnO (11$ \bar 2 $0) substrates by using the plasma‐assisted reactive evaporation (PARE) method. The value of FWHM of the ω‐scan rocking curve of non‐doped ZnO (11$ \bar 2 $0) films were 26 to 62 arcseconds. Crystallinity of ZnO (11$ \bar 2 $0) films deteriorated with increase in N2 gas flow rate, but crystallinity of the films was better than that of ZnO (11$ \bar 2 $0) films grown on sapphire (11$ \bar 2 $0) substrates by the PARE method. Independently of N2 gas flow rate, AFM images of non‐polar ZnO films showed a smooth surface with about 1 nm of root mean square roughness. In near band‐edge PL spectra from these non‐doped ZnO films measured at 5 K, free‐exciton emission (FE) at about 3.378 eV, ionized‐donor‐bound excitons (D+X) at about 3.368 eV and neutral‐donor‐bound excitons (D0X) at about 3.362 eV were clearly observed. PL intensity of D+X of non‐polar ZnO:N films was decreased but that of donor‐acceptor pairs (DAP) emission at around 3.308 eV of the films increased with an increase in N2 gas flow rate. It is thought that N atoms occupied oxygen sites and surface state density were decreased with increase in N2 gas flow rate and that N atoms act as acceptors in ZnO. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Contributedmentioning

confidence: 72%

Section: Contributedmentioning

confidence: 96%

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confidence: 99%

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Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Abe

Nakagawa

Chiba

et al. 2009

Phys. Status Solidi (c)

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“…Large grain structures were observed in the AFM image of the ZnO (1120) film grown at a T s of 800 °C. Striped patterns have been observed on ZnO (1120) films epitaxially grown on sapphire (0112) [19] and ZnO (1120) substrates [20]. In Refs.…”

Section: Methodsmentioning

confidence: 99%

Heteroepitaxial growth of non‐polar ZnO films on single crystal NdGaO₃ (001) substrates by MOCVD

Kashiwaba

Yokoyama

Sakuma

et al. 2014

Phys. Status Solidi C

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High‐quality non‐polar ZnO (11$ \bar 2 $0) films were epitaxially grown on single crystal NdGaO3 (NGO) (001) substrates. The non‐polar ZnO (11$ \bar 2 $0) films were grown by metal organic chemical vapour deposition using Zn(C5H7O2)2 and O2 gas as starting materials. X‐ray diffraction (XRD) peaks of ZnO (11$ \bar 2 $0) plane were observed in XRD patterns of 2θ‐ω scans in all films. Rotation domains were not found in XRD φ scan patterns of ZnO (11$ \bar 2 $0) films grown at a substrate temperature of 650 °C or less. XRD peaks of NGO (021) and ZnO (11$ \bar 2 $2) planes were observed at the same angle φ in the XRD φ scan patterns. The epitaxial relationship was ZnO (11$ \bar 2 $0)// NGO (001) and ZnO [0001] // NGO [010]. Lattice mismatch values along the ZnO [0001] direction and along the ZnO (1$ \bar 1 $00) direction were 5.36% and –3.70%, respectively. Growth rate was drastically decreased at the substrate temperature over 650 °C. Striped patterns along the ZnO [0001] direction were observed in atomic force microscopy images of ZnO (11$ \bar 2 $0) films grown at substrate temperatures of 600 and 650 °C. Emissions due to donor‐bound excitions were observed in photoluminescence spectra of ZnO (11$ \bar 2 $0) films measured at 10 K. It is thought that NGO (001) substrates are useful for growth of high‐quality non‐polar ZnO (11$ \bar 2 $0) films. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Therefore and by considering the epitaxial relationships of ZnO on r-plane [12,18,19,[23][24][25][26][27] ZnO 1100 //Al O 1120 …”

Section: Structural Propertiesmentioning

confidence: 99%

Structural, Morphological, Optical and Electrical Properties of Zn(1-x)CdxO Solid Solution Grown on a- and r-Plane Sapphire Substrate by MOCV

Fouzri¹,

Boukadhaba²,

Tauré³

et al. 2013

JCPT

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Zn (1−x) Cd x O films have been grown on  1120  (a-plane) and   0112 (r-plane) sapphire substrate by metal organic chemical vapor deposition. A maximum cadmium incorporation of 8.5% and 11.2% has been respectively determined for films deposited on a-and r-plane sapphire. The optical transmission spectra and energy band-gap equation established by Makino et al. were used to estimate the cadmium mole fraction of the solid solutions. Structural, morphological and optical properties of these films were examined using high resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and room and low temperature photoluminescence (Pl) as Cd incorporation and employed substrate. X-ray diffraction study revealed that all films had wurtzite phase but solid solution grown on a-plane sapphire are polycrystalline with a preferred orientation along the [0001] direction and a-plane   1120 film are epitaxially grown on r-plane sapphire. AFM image show significant differences between morphologies depending on orientation sapphire substrate but no significant differences on surface roughness have been found. The near band-edge photoluminescence emission shifts gradually to lower energies as Cd is incorporated and reaches 2.916 eV for the highest Cd content (11.2%) at low temperature (20 K). The room temperature hall mobility decreases with the Cd incorporation but it is larger for Zn (1−x) Cd x O grown on r-plane sapphire.

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Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy

Cited by 94 publications

References 18 publications

Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Heteroepitaxial growth of non‐polar ZnO films on single crystal NdGaO₃ (001) substrates by MOCVD

Structural, Morphological, Optical and Electrical Properties of Zn<sub>(1-x)</sub>Cd<sub>x</sub>O Solid Solution Grown on <i>a</i>- and <i>r</i>-Plane Sapphire Substrate by MOCV

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Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy

Cited by 94 publications

References 18 publications

Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates

Heteroepitaxial growth of non‐polar ZnO films on single crystal NdGaO3 (001) substrates by MOCVD

Structural, Morphological, Optical and Electrical Properties of Zn&lt;sub&gt;(1-x)&lt;/sub&gt;Cd&lt;sub&gt;x&lt;/sub&gt;O Solid Solution Grown on &lt;i&gt;a&lt;/i&gt;- and &lt;i&gt;r&lt;/i&gt;-Plane Sapphire Substrate by MOCV

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Heteroepitaxial growth of non‐polar ZnO films on single crystal NdGaO₃ (001) substrates by MOCVD

Structural, Morphological, Optical and Electrical Properties of Zn<sub>(1-x)</sub>Cd<sub>x</sub>O Solid Solution Grown on <i>a</i>- and <i>r</i>-Plane Sapphire Substrate by MOCV