2006 Fiscal Year Final Research Report Summary
Surfactant MBE of ZnO and its applications to the growh of p-type doping
| Project/Area Number |
17360001
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
YAO Takafumi Tohoku University, Center for Interdisciplinary Research, Professor, 学際科学国際高等研究センター, 教授 (60230182)
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| Co-Investigator(Kenkyū-buntansha) |
MEOUNG-WHAN Cho Tohoku University, Institute Materials Research, Associate Professor, 金属材料研究所, 助教授 (00361171)
HANADA Takashi Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (80211481)
INHO Im Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (00400408)
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| Project Period (FY) |
2005 – 2006
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| Keywords | ZnO / nitride semiconductors / epitaxial growth / MBE / surfactant |
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| Research Abstract |
We have succeeded in developing surfactant MBE of ZnO layers doped with N. The purposes of the research include:
(1) development of ZnO layers at low temperatures and (2) development of high concentration of doping of nitrogen. The growth temperature for high-quality undoped ZnO layers on ZnO homoepitaxy substrates is lowered down to 400 ーC, which should be compared with the conventional growth temperature of 700゜C. XRD studies show the FWHM values for (0002) and (10-10) to be 30 arcsec and 40 arcsec, respectively. It should be stressed that these values are quite narrow and indicate high quality ZnO layers.
We have tried nitrogen doping under hydrogen exposure at low temperatures in addition to nitrogen doping under conventional MBE. We have found that nitrogen doping onto Zn-polar ZnO layers are more efficient compared with 0-polar ZnO layers by almost one-order of magnitude. We have also found that as the growth temperature is lowered, the efficiency for nitrogen doping is greatly enhanced. At the growth temperature of 350 ℃, the nitrogen concentration increases up to 10^<20>cm^<-3>. Detailed photoluminescence studies suggest the formation of acceptor level of 180 meV. However, the nitrogen-doped ZnO shows n-type conductivity. We speculate that this is correlated with the formation N-H bonding, which should passivate N atoms. We tried annealing to remove hydrogen from the samples. Some of the samples show p-type conductivity, but show poor reproducibility presumably due to instability of the surface.
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[Journal Article] Selective Growth of Vertically-Aligned ZnO Nano-Needles.2006
Author(s)
SH Lee, WH Lee, SW Lee, H Goto, T Baba, MW Cho, T Yao, HJ Lee, T Yasukawa, T Matsue, H Ko
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Journal Title
Journal of Nanoscience and Nanotechnology 6
Pages: 3351-3354
Description
「研究成果報告書概要(和文)」より
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