2004 Fiscal Year Final Research Report Summary
Separate Evaluation of Electron Coherence Influence Factors in Quantum Device by Resonant Tunneling Structures
| Project/Area Number |
15560291
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electron device/Electronic equipment
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MACHIDA Nobuya Tokyo Inst.Tech., Graduate Course of Science and Engineering, Assistant Professor, 大学院・理工学研究科, 助手 (70313335)
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| Project Period (FY) |
2003 – 2004
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| Keywords | hot electron / resonant tunneling diode / phase coherence / structural inhomogeneity / phase correlation function / electron interference / quantum effect device / semiconductor |
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| Research Abstract |
The objective of the research is to clarify a possibility to separately evaluate electron coherence influence factors, that is, phase relaxation, structural inhomogeneity, and temperature, by using IV characteristics of resonant tunneling diode(RTD).
We proposed an evaluation method of electron coherence by IV characteristics of RTD. In the method, IV curves are divided into three regions, that is, a)current cut-off region, b)current raising region, and c)current peak region. By fitting experimentally measured IV curve completely, electron phase coherence and structural inhomogeneity can be evaluated from region a)and b)respectively.
To confirm effectiveness of present method, we evaluated a InP/InGaAs RTD which was grown by the step flow mode. IV data measured at 4.2K was completely fitted over three orders in current magnitude from region a)to c)by assuming well width fluctuation of 0.6 nm, and we confirmed the effectiveness of our proposed method.
Next, we modeled the influence of random distribution of impurities in the emitter and collector electrodes on IV characteristics. Then, we found the condition that the influence on the a)region was quite small. For example, the influence was suppressed with a spacer layer of length 2.6nm when a doping density was 3x10^<17>cm^<-3>.
Finally, by using the theoretical method obtained thus far, we succeeded to give a RTD structure where the electron coherence could be evaluated separately.
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