2002 Fiscal Year Final Research Report Summary
Fabrication of Si-based room temperature infrared light-emitting diodes using β-FeSi_2
| Project/Area Number |
12555084
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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 | 展開研究 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SUEMASU Takashi University of Tsukuba, University of Tsukuba Institute of Applied Physics, Lecturer (40282339)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Fumio University of Tsukaba, Institute of Applied Physics, Professor (70143170)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Iron disilicide / photoluminescence / light-emitting diode / electroluminescence |
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| Research Abstract |
The purpose of this work is to fabricate infrared light-emitting diodes (LEDs) using semiconducting β-FeSi_2 which operate at room temperature (RT). In the term of this project, we have realized RT 1.6μm electroluminescence (EL) from p-Si/β-FeSi_2 particles/n-Si LEDs for the first time. It was found that the luminescence from β-FeSi_2 particles embedded in Si was very sensitive to the following growth conditions.
1. The photoluminescence (PL) intensity of β-FeSi_2 strongly depends on MBE-Si growth temperature for embedding β-FeSi_2 in Si. When the Si overlayer was grown at lower temperatures of 400-500℃, the PL was intense. In contrast, the PL was very weak and was difficult to detect when it was grown at higher temperatures of 600-750℃. It was found that about 9% tensile strain was introduced into the particles in the [100] direction of β-FeSi_2, making the β-FeSi_2 a direct band gap semiconductor.
2. PL was found to be sensitive to the size of β-FeSi_2 particles embedded in Si matrix. The PL intensity increased with the size of β-FeSi_2, but the intensity of 1.2-1.4μm broad PL also increased for samples with β-FeSi_2 bigger than 200nm. Transmission electron microscopy observation revealed that dislocations were introduced around the particles for those samples.
3. PL was found to improve significantly by optimizing p-Si growth temperature and its boron concentration. Dislocation and point defects were found to be generated by oxygen incorporated in to the heavily boron-doped Si layer during the 14h of thermal annealing at 900℃, and are suggested to be responsible for the quenching of the PL.
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