Single Domain m-Plane ZnO Grown on m-Plane Sapphire by Radio Frequency Magnetron Sputtering

Lin, Bi‐Hsuan; Liu, W.-R.; Lin, Chen‐Yuan; Hsu, Shun-Chieh; Yang, Song; Kuo, C. C.; Hsu, Chi‐Hsin; Hsieh, Wen–Feng; Chien, Fan Ching; Chang, Chen

doi:10.1021/am301271k

Cited by 16 publications

(13 citation statements)

References 20 publications

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“…ZnO nanostructures have found many applications in fabricating electronic, optoelectronic, electrochemical devices, and electromechanical devices, such as ultraviolet (UV) lasers [4,5], light-emitting diodes [2,6,7], thin-film transistors [8,9], field emission (FE) devices [10,11], solar cells [12], and piezo-nanogenerator [13,14]. In general, ZnO nanostructures are typically manufactured by thermal evaporation [3,15], metal organic chemical vapor deposition [16], pulsed laser deposition [17], spray pyrolysis [18], epitaxial electrodeposition [19], and radiofrequency magnetron sputtering [20]. Recently, a facile fabrication technique of aqueous chemical growth (ACG) has been demonstrated to grow three-dimensional (3D) ZnO nanorods [21,22], ZnO nanotubes [23], ZnO nanowires [24], ZnO nanoplates [25], ferric oxide nanorods [26], and tin dioxide nanorods [27].…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependence cathodoluminescence of ultra-sharp ZnO nanopagoda arrays

Chang

2014

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Temperature-dependence cathodoluminescence of ultra-sharp ZnO nanopagoda arrays

Chang

2014

Journal of Alloys and Compounds

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“…However, defects are easily generated in epitaxial ZnO films on the sapphire due to the large lattice mismatch of 18 % [14], including misfit dislocations [15,16] and twin domains [14,17,18]. On the other hand, increasing attentions are paid to obtain in-plane polar epitaxial ZnO films, such as (10-10)-oriented (m-plane) and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)-oriented (a-plane) ones [19]. It is known that ZnO has its intrinsic electrical polarity along the c-axis in the wurtzite structure, and thus, the c-ZnO thin films inevitably suffer the quantum-confined Stark effect (QCSE), which reduces the exciton binding energy and limits the optical performance.…”

mentioning

confidence: 99%

“…The c-ZnO thin film exhibits the sixfold symmetry. In details, the epitaxy relationship is described by ZnO [11][12][13][14][15][16][17][18][19][20]//STO [1][2][3][4][5][6][7][8][9][10] and ZnO [11][12][13][14][15][16][17][18][19][20]//STO [2-1-1]. The lattice mismatch between ZnO and STO in this epitaxy mode is only *1.9 %, much smaller than that between c-ZnO and sapphire, and the lattice match geometry is schematically shown in Fig.…”

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confidence: 99%

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Enhanced near-band-edge emission from a-plane ZnO thin films on SrTiO3 substrates

Liu

et al. 2015

Appl. Phys. A

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Epitaxial ZnO with controlled orientations is highly concerned, and we report epitaxial growth of (0001)-and (11-20)-oriented ZnO films, respectively, on (111)-and (100)-SrTiO 3 (STO) substrates using pulsed laser deposition. The epitaxial growth of (11-20)-ZnO films on (100)-STO, with in-plane orientation relationship of ZnO [0001]//STO [110] and ZnO [10-10]//STO [1-10], is realized. It is revealed that the (11-20)-ZnO films have much stronger photo-luminescence (PL) intensity than those of the (0001)-oriented ones, while the electric conductance remains comparable with the latter. The electrical and PL properties of the (11-20)-ZnO films are correlated with the in-plane polarity.Zinc oxide (ZnO) is one of the most extensively investigated semiconductors [1][2][3]. In the ambient conditions, it crystallizes in wurtzite structure, which has a hexagonal unit cell with the P6 3 mc space group and lattice parameters a = 0.32475 nm and c = 0.52042 nm. Widespread interest in ZnO is fueled by its prospects in optoelectronics applications [4,5]. It is known that ZnO and GaN both have wide band-gap (E g ) of *3.3 eV at 300 K. However, ZnO shows some advantages over GaN, such as the availability of high-quality ZnO single crystals and thin films, resulting in a potentially low cost for processing relevant devices. The most attractive advantage of ZnO over GaN is the high exciton binding energy which is 25 meV for GaN but 60 meV for ZnO, while the roomtemperature (RT) thermal energy is *25 meV [6]. This allows the specific preference of ZnO for intense nearband-edge exciton emission at higher temperatures.Another well-recognized application associated with ZnO is transparent thin-film transistor [7], where the protective covering preventing light exposure is eliminated since ZnO-based transistors are insensitive to visible light. More importantly, a carrier density up to 2 9 10 21 cm -3 can be reached in ZnO by heavy substitution [8], allowing the electrical properties to be modulated in a broad regime, while its optical transparency remains robust, making it useful for transparent electrodes [9, 10]. These advantages even promise ZnO as a material for spintronics since good magnetic properties can be induced by magnetic substitutions [11].Along this line, high-quality ZnO epitaxial films with different orientations are highly appealed for developing ZnO-based devices. Successful preparations of (0001)-oriented ZnO (c-ZnO) films on various substrates including sapphire have been well reported [12,13]. However, defects are easily generated in epitaxial ZnO films on the sapphire due to the large lattice mismatch of 18 % [14], including misfit dislocations [15,16] and twin domains [14,17,18]. On the other hand, increasing attentions are paid to obtain in-plane polar epitaxial ZnO films, such as (10-10)-oriented (m-plane) and (11-20)-oriented (a-plane) ones [19]. It is known that ZnO has its intrinsic electrical polarity along the c-axis in the wurtzite structure, and thus, the c-ZnO thin films inevitably suffer the quantum-c...

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“…Up to now, many kinds of oriented ZnO epilayers, e.g. c-, a-and m-plane ZnO, have been grown on various sapphire substrates [6,7]. However, a significant number of dislocations and stacking faults exist in these epi-films, seriously degrading their optical properties.…”

mentioning

confidence: 99%

Growth of epitaxial c ‐plane ZnO film on a ‐plane sapphire by radio frequency reactive magnetron sputtering

Liu

Gao

Zeng

et al. 2013

Physica Rapid Research Ltrs

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In recent years, zinc oxide (ZnO) has drawn great attention as a promising material for optoelectronics and other applications due to its versatile attributes, such as wide band gap (3.37 eV), large exciton binding energy (60 meV), large piezoelectric response (12 pC/N) and environmentally friendly performance, etc. [1][2][3]. For application in optoelectronics, many efforts have been devoted to growing ZnO epi-films on different substrates [4,5], among which the sapphire is the most commonly used substrate. Up to now, many kinds of oriented ZnO epilayers, e.g. c-, a-and m-plane ZnO, have been grown on various sapphire substrates [6,7]. However, a significant number of dislocations and stacking faults exist in these epi-films, seriously degrading their optical properties. A facile approach to surmount this problem is by choosing a substrate with less lattice mismatch to the epitaxial ZnO film. Based on the fact that the four-fold of the ZnO lattice constant a fits perfectly with the lattice constant c of sapphire with a mismatch of less than 0.08% [8], a-plane sapphire is intentionally chosen as the substrate in this study.To date, the growth of c-plane ZnO epilayer on a-plane sapphire substrate has been achieved by using chemical vapor deposition (VPD) [8] and molecular-beam epitaxy (MBE) [9]. However, few works have been reported to grow epitaxial c-plane ZnO on a-plane sapphire by using radio frequency reactive magnetron sputtering (RF-RMS), which is a popular film deposition method and has been widely used in industrial thin film fabrication due to its easy process and ability for large-scale production with relatively low cost. More importantly, using RF-RMS it is easy to tailor the resistivity by varying the oxygen partial pressure, to tune the film compositions by changing the power of zinc target and other targets for co-sputtering. Herein, we employ RF-RMS to grow epitaxial ZnO films on a-sapphire substrates, and investigate the influence of dislocation density on the photoluminescence (PL) characteristics. A linear relationship between screw density and the full width at half maximum value of the PL near-bandedge emission is established.A series of ZnO films with nominal thickness of 200 nm were deposited on a-plane sapphire substrates at various temperatures by RF-RMS within a mixture of pure argon (99.999%) and oxygen (99.999%) gases. The target material was 3 inch diameter zinc with purity of 99.999%In this Letter, we report the successful growth of high quality c-plane oriented epitaxial ZnO films on a-plane sapphire substrates by using radio frequency reactive magnetron sputtering. The effect of substrate temperature on the structural and optical properties has been investigated. X-ray diffraction (XRD) studies reveal that the ZnO film is grown epitaxially on a-plane sapphire substrate, and the film quality is improved as the substrate temperature is increased. Photoluminescence (PL) results manifest that screw dislocations can exert great influence on the optical properties. It is found that the l...

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Single Domain m-Plane ZnO Grown on m-Plane Sapphire by Radio Frequency Magnetron Sputtering

Cited by 16 publications

References 20 publications

Temperature-dependence cathodoluminescence of ultra-sharp ZnO nanopagoda arrays

Temperature-dependence cathodoluminescence of ultra-sharp ZnO nanopagoda arrays

Enhanced near-band-edge emission from a-plane ZnO thin films on SrTiO3 substrates

Growth of epitaxial c ‐plane ZnO film on a ‐plane sapphire by radio frequency reactive magnetron sputtering

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