1997 Fiscal Year Final Research Report Summary
New STM technique for observation of ballistic electrons in semiconductors
| Project/Area Number |
08405023
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
FURUYA Kazuhito Tokyo Institute of Technology Faculty of Engineering Professor, 工学部, 教授 (40092572)
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| Co-Investigator(Kenkyū-buntansha) |
SUHARA Michihiko Research Center for Quantum Effect Electronics Research Assistant, 量子効果エレクトロニクス研究センター, 助手 (80251635)
MIYAMOTO Yasuyuki Tokyo Institute of Technology Faculty of Engineering Associate Professor, 工学部, 助教授 (40209953)
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| Project Period (FY) |
1996 – 1997
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| Keywords | hot electron / STM / hot electron emitter / noise in tunnel current / noise reduction by phase sensitive detection / low work function metal |
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| Research Abstract |
We have proposed and proved a new STM technique, Scanning Hot Electron Microscopy (SHEM), which has detected ballistic hot electrons (HE) propagating towards a surface of a solid material by a probe of STM to measure a spatial distribution and an energy spectrum of the HE.To lower the potential peak between the tip and the surface down to the HE energy, we have derived theoretical relation required for the work functions of the tip and the surface, the tunnel voltage and the tip-surface spacing. We have designed an experiment which has verified our idea in an atmospheric environment. We have selected Si/CaF2/Au heterostructure, analyzed self-consistently a band profile under the bias voltage application to show a possibility of generation of the hot electron with energy of 3eV at current density of 10KA/cm2. We have fabricated hot electron emitters with the area of 10um2 by using photolithography to obtain emission characteristics as designed. We have measured the phase sensitive detec
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tion (PSD) output approaching of the tip to the surface under application of DC voltage of 3V,AC voltage of 170mV at frequency of 82Hz to the emitter and the tunnel voltage of 1.5V.When the tip approached to the sample within certain distance, the output increased suddenly to show the hot electron detection, which was the first detection of the HE by the scanning probe tip. However, it took quite long time for integration to take one data point against the noise. We have theoretically obtained the optimum condition for the detection with respect to the immunity for the tip vibration. We have developed digital recording and processing system of the tunnel current to analyze the noise characteristics and to extract HE signal. It has been made clear from the power spectrum analysis and the above theory that 1pA HE signal can be detected by the PSD at integration time of 10sec. We have established the technique to obtain systematic data of SHEM through this research. The measurement of the spatial distribution of HE and the detection of the hot electron in the semiconductor has been left as the next stage targets. Less
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