1993 Fiscal Year Final Research Report Summary
Size Reduction of Crystalline Silicon in Anodized Porous Silicon by Partial Oxidation for Stable Visible Luminescence
| Project/Area Number |
04452094
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Osaka University |
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Principal Investigator |
ITO Toshimichi Osaka University, Department of Electrical Engineering Associate Professor, 工学部, 助教授 (00183004)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Porous Silicon / Microcrystallne Silicon / Visible Luminescence / Phtoluminescence / Electroluminescence / Quantum Size Effect / Anodic Oxidation / Plasma Oxidation |
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| Research Abstract |
The structural instability of porous silicon (PS) formed by anodization in a HF solution is one of problems to be overcome. In the present research, stabilization of the PS structure was achieved by means of thermal, anodic and plasma oxidations, leading to roomtemperature luminescence from oxidized PS in red to blue-green regions. We also found that considerable amount of hydrogen (more than 10 at%) were contained even in PS oxidized thermally at high temperatures.
In the case of PS anodically oxidozed, it was found that peaks of photoluminescence(PL) and PL excitation spectra shifted to the higher energy side with increasing oxidation at the initial stage while the PL blushift was saturated for sufficient oxidation, meaning widening of the bandgap of Si crystallites in PS due to the size reduction effect as well as appearance of luminescence centers in the widened bandgap. The temperature dependence of PL spectra indicated the presence of several levels related to the centers.
Electroluminescence(EL) spectra were observed from anodically oxidized PS specimens with shallow PN junctions. EL intensities were found to increase more strongly than linear dependence of injection current density, suggesting the importance of hot carrier effects on EL.For plasma-oxidized PS specimens, we found that hydrogen plasma treatment was required to compensate defects created in the oxide in PS durying the oxidation.
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Research Products
(15 results)
