Growth mechanism of ZnO deposited by nitrogen mediated crystallization

Suhariadi, Iping; Shiratani, Masaharu; Itagaki, Naho

doi:10.1088/2053-1591/1/3/036403

Cited by 8 publications

(5 citation statements)

References 41 publications

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“…The growth rate in the c-direction is hence considerably reduced when growing homoepitaxially in a partial N 2 atmosphere, suggesting that N 2 inhibits nucleation, forcing adatoms to migrate longer distances before chemisorbing, effectively increasing the adatom mobility and the desorption rate. Similar effects have been reported for (i) polycrystalline sputter growth of ZnO, where N suppresses the nucleation of grains by increasing the nucleation energy barrier [160,161]; (ii) Si oxidation where the growth rate of SiO 2 was significantly reduced by an increase in the area density of surface N either due to "neutralization of oxide growth sites" or due to N acting as a diffusion barrier for O [162]; and (iii) Metal Organic Vapor Phase Epitaxy grown ZnSe where N reduced the growth rate because N adsorbed to the surface inhibiting reaction between the Se-terminated surface and Zn-containing precursors [163]. The increase in adatom mobility and desorption rate from N inhibition of nucleation sites, favors in-plane growth over c-direction growth and hence lowers the growth rate.…”

Section: Homoepitaxial Growth Of Zno By Rf-magnetron Sputteringsupporting

confidence: 83%

Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

Riise

Schumann

Azarov

et al. 2015

Applied Physics Letters

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This thesis explores various processing and materials aspects of an oxide solar cell. A tandem structure consisting of a Silicon (Si) bottom cell, and a Cuprous Oxide (Cu 2 O)/Zinc Oxide (ZnO) top cell is suggested, and several materials challenges relevant for the design is addressed. Using Flash Lamp Annealing, shallow p-type emitters are produced in Si by indiffusion of Boron (B) from a surface source. The B diffusion is shown to be enhanced by a transient of Si interstitials originating from the surface coating. The n ++-side of a Si tunneling junction is realized by sputter depositing highly Phosphorus (P) doped Si thin films on quartz. The P activation and thin film conductivity are highest after prolonged, high temperature annealing, and thin film roughness is significantly reduced after a Reactive Ion Etch treatment of the quartz substrates. A rectifying Cu 2 O/Si heterojunction is demonstrated, and most of its depletion layer is located in Si showing that the acceptor concentration in the sputtered Cu 2 O is significantly higher than 1.1×10 17 cm −3. Epitaxial growth of Cu 2 O is realized on single crystal ZnO, and XRD measurements reveal that the Cu 2 O grows in two separate [111]-oriented domains which are rotated 180 • relative to each other. Further, a thin, detrimental layer of CuO is evidenced by TEM at the interface between the sputtered Cu 2 O and the ZnO single crystal. Homoepitaxial sputter growth of ZnO is investigated in some detail, and the growth is found to depend on sputter target power density, substrate polarity, and growth ambient. Specifically, c-axis growth is promoted when growing on the Zn-face of ZnO, while slower, in-plane growth is promoted during O-face growth and during growth in a Nitrogen ambient. Treating sputter grown Cu 2 O thin films by Rapid Thermal Annealing is demonstrated by XRD, PL and Hall effect measurements to be highly beneficial for the thin film structural quality. Finally, two band gap defects in Cu 2 O are revealed using Temperature Dependent Hall effect measurements, and the defect ionization energy values are found to be dependent on sample strain.

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Section: Homoepitaxial Growth Of Zno By Rf-magnetron Sputteringsupporting

confidence: 83%

Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

Riise

Schumann

Azarov

et al. 2015

Applied Physics Letters

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“…Role of polycrystalline ZnO buffer layers is to form nucleation sites for the growth of ZnO single crystal films. 38,39,43) In case of ZnO film reported in Ref. 43, a thin ZnO buffer layer with small grains (100 nm size) using the Zn(CH 3 COO) 2 solution was overgrown by a ZnO film with large grains (micrometer size) using the ZnCl 2 solution, forming high-quality ZnO films.…”

Section: Discussionmentioning

confidence: 99%

“…However, the problem of lattice mismatch still exists. To overcome lattice mismatch, several methods have been reported, such as inserting a buffer layer between the film and the substrate, [38][39][40][41][42][43] changing the lattice constant of the substrate surface by doping, 44) and changing the type of solution for film formation. 39) In this study, we focused on the improvement of the crystal quality mainly in a viewpoint of FWHM in XRD rocking curve.…”

Section: Introductionmentioning

confidence: 99%

“…To overcome lattice mismatch, several methods have been reported, such as inserting a buffer layer between the film and the substrate, [38][39][40][41][42][43] changing the lattice constant of the substrate surface by doping, 44) and changing the type of solution for film formation. 39) In this study, we focused on the improvement of the crystal quality mainly in a viewpoint of FWHM in XRD rocking curve. To improve the crystal quality of the SnO 2 films, we previously reported the insertion of a SnO 2 buffer layer between the SnO 2 film and an m-plane sapphire substrate by mist-CVD, 41) where surface smoothness of the SnO 2 film was much improved.…”

Section: Introductionmentioning

confidence: 99%

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Improvement of tin oxide single crystal on anm-plane sapphire substrate by mist chemical vapor deposition

Win¹,

Kobayashi²,

Furukawa³

et al. 2020

Jpn. J. Appl. Phys.

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We successfully improved quality of tin oxide (SnO2) films formed on m-plane sapphire substrates by mist chemical vapor deposition. The crystal quality was characterized mainly by the FWHM of the X-ray diffraction ω-rocking curve. We found that the use of tin acetate [Sn(CH3COO)4] solution led to the formation of high-quality SnO2 film, where FWHM was as narrow as 0.1°. Using tin chloride (SnCl4) solution, electrical and optical properties can be improved because crystal grain size was large. Therefore, on the SnO2 layer formed with the Sn(CH3COO)4 solution, the second SnO2 layer was overgrown with the SnCl4 solution to form a double-layer structure, where FWHM was also 0.1° and carbon impurity was lower than that of the first SnO2 layer. Furthermore, in case of the second SnO2 layer, we found that a growth temperature window providing the narrow FWHM of 0.1° was very wide (500 °C–800 °C).

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“…S1), which is 4-5 orders of magnitude lower than the oxygen concentration in the film. This low nitrogen concentration in the film is due to the low solubility in ZnO 27,47,48 , and this property of nitrogen is what we consider to lead to grain size decrease. That is, the low solubility makes N-atoms segregate on the surface as well as at the grain boundaries, and thus lower the surface free energy per unit area [31][32][33][34] .…”

Section: Role Of Impuritymentioning

confidence: 93%

Growth of single crystalline films on lattice-mismatched substrates through 3D to 2D mode transition

Itagaki

Nakamura

Narishige

et al. 2020

Sci Rep

Self Cite

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Regarding crystalline film growth on large lattice-mismatched substrates, there are two primary modes by which thin films grow on a crystal surface or interface. They are Volmer-Weber (VW: island formation) mode and Stranski-Krastanov (SK: layer-plus-island) mode. Since both growth modes end up in the formation of three-dimensional (3D) islands, fabrication of single crystalline films on lattice-mismatched substrates has been challenging. Here, we demonstrate another growth mode, where a buffer layer consisting of 3D islands initially forms and a relaxed two-dimensional (2D) layer subsequently grows on the buffer layer. This 3D-2D mode transition has been realized using impurities. We observed the 3D-2D mode transition for the case of ZnO film growth on 18%-lattice-mismatched sapphire substrates. First, nano-sized 3D islands grow with the help of nitrogen impurities. Then, the islands coalesce to form a 2D layer after cessation of the nitrogen supply, whereupon an increase in the surface energy may provide a driving force for the coalescence. Finally, the films grow in 2D mode, forming atomically flat terraces. We believe that our findings will offer new opportunities for highquality film growth of a wide variety of materials that have no lattice-matched substrates.

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Growth mechanism of ZnO deposited by nitrogen mediated crystallization

Cited by 8 publications

References 41 publications

Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

Improvement of tin oxide single crystal on anm-plane sapphire substrate by mist chemical vapor deposition

Growth of single crystalline films on lattice-mismatched substrates through 3D to 2D mode transition

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