Polarity control and growth mode of InN on yttria‐stabilized zirconia (111) surfaces

Applied Physics Letters

et al. 2013

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An In-polar InN ultrathin film with high electron mobility was grown on an insulating yttria-stabilized zirconia (YSZ) (111) substrate via precise control of growth conditions for initial monolayers. It was found that the first several monolayers of InN on YSZ can be grown in a two-dimensional mode using extremely N-rich (ex-N-rich) conditions. Although the growth of more than several InN monolayers under these conditions results in rough surfaces, probably because of the suppressed migration of In atoms on the surface, the combination of ex-N-rich growth for the first few monolayers with subsequent conventional In-rich growth leads to the successful formation of InN films with smooth surfaces. The electron mobility of 11-nm-thick InN on YSZ with two-dimensionally grown initial layers was 170 cm2 V−1 s−1, which is much higher than the best reported value for InN ultrathin layers grown on GaN substrates. These results indicate that the structural quality of the InN/YSZ heterointerface and a smooth surface are inherently important for obtaining InN ultrathin films with good transport properties.

mentioning

confidence: 99%

“…Details of surface treatment of YSZ surfaces for the polarity control of c-plane InN have been reported. 14,15 In-polar InN ultrathin films were grown on YSZ (111) substrates using pulsed sputtering deposition. 16 An In metal target (99.9999% purity) and nitrogen gas were used as group III and V sources, respectively.…”

mentioning

confidence: 99%

Electron mobility of ultrathin InN on yttria-stabilized zirconia with two-dimensionally grown initial layers

Okubo

Applied Physics Letters

et al. 2013

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“…The growth temperatures for the In‐polar (0001) and N‐polar $(000\bar 1)$ InN films were set at 430 °C and 500 °C, respectively. The details of surface treatment of YSZ substrates for polarity control of InN films is reported elsewhere 15. The full width at half maximum for the X‐ray rocking curves of 0002 and $10\bar 10$ diffractions were 535 and 1577 arcsec for the In‐polar InN and 1314 and 1710 arcsec for the N‐polar InN films, respectively.…”

Section: Methodsmentioning

confidence: 99%

Solid‐phase epitaxy of InO_x N_y alloys via thermal oxidation of InN films on yttria‐stabilized zirconia

Itoh

Physica Rapid Research Ltrs

et al. 2014

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The characteristics of InOx Ny alloy films prepared via thermal oxidation of InN epitaxial films with In‐ or N‐polarities grown on nearly lattice‐matched, yttria‐stabilized zirconia (YSZ) substrates are investigated. The InN films were oxidized to InOx Ny with a gradual change in O/N composition by annealing in air. Structural analysis revealed that the temperature for phase transition from wurtzite structure depends on the polarity of InN, and N‐polar InOx Ny films can retain their wurtzite structure even at higher temperatures compared with the case of In‐polar films. Furthermore, changes in the valence band structure and optical characteristics of the InOx Ny alloys take place via thermal oxidation. These results indicate that InOx Ny grown via thermal oxidation of N‐polar InN on YSZ can be considered as an alloy semiconductor for optoelectronic devices. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

“…Semipolar InN substrates might be useful in suppressing quantum‐confined Stark effects in InGaN quantum wells, which have potential applications in high‐efficiency solar cells and light‐emitting devices. The YSZ substrate also makes it possible to grow both In and N‐polar ( c ‐plane) InN films . The surface of a YSZ substrate capped with another YSZ wafer and annealed at high temperature is covered by Y atoms, and Y segregation leads to the growth of In‐polarity InN.…”

Section: Introductionmentioning

confidence: 99%

“…The YSZ substrate also makes it possible to grow both In and N-polar (c-plane) InN films. [22] The surface of a YSZ substrate capped with another YSZ wafer and annealed at high temperature is covered by Y atoms, and Y segregation leads to the growth of In-polarity InN. On the other hand, annealing a YSZ substrate capped with a sapphire wafer suppresses the segregation of Y atoms on the surface, resulting in the growth of N-polar InN.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial Growth of Thick Polar and Semipolar InN Films on Yttria‐Stabilized Zirconia Using Pulsed Sputtering Deposition

Oseki

Physica Status Solidi (b)

et al. 2017

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We grew thick InN films on yttria‐stabilized zirconia (YSZ) substrates by high‐growth‐rate pulsed sputtering deposition. X‐ray diffraction analysis revealed that the in‐plane orientation distribution of the InN (0001) films on YSZ decreased as the film thickness increased. The edge dislocation density of the 9.0‐µm‐thick InN film grown at a rate of 6 µm h−1 is calculated to be 1.7 × 109 cm−2, and the atomically flat surface exhibited a step‐and‐terrace structure. In addition, the crystallinity of semipolar InN is improved by increasing the film thickness. These results indicate that high‐growth‐rate pulsed sputtering deposition can be used to prepare InN substrates for the fabrication of high‐speed electron devices and InGaN‐based, long‐wavelength light‐emitting devices.