Light Emission from Metal-Oxide-Semiconductor Tunneling Diodes and the Strain Effect
Date Issued
2006
Date
2006
Author(s)
Guo, Tsai-Hua
DOI
en-US
Abstract
In this thesis, the metal-oxide-semiconductor (MOS) tunneling diodes were utilized as light emitting diodes based on that the tunneling gate current recombines with accumulated majority carriers and results in radiative luminescence. We used liquid phase deposition (LPD) method in stead of traditional thermal method to deposit oxide films, and the LPD has higher efficiency due to more defects in it. We brought up a mechanical set up to apply external tensile strain. The reduction of Si band gap and the enhancement of light intensity under external tensile strain are observed. The upshift of valence band edge and the downshift of conduction band edge under tensile strain are responsible for that. The upshift of valence band edge under mechanical strain increases the majority hole concentration at the oxide/Si interface. The SiGe QD and Si/Ge heterojunction MOS LED were reported in this thesis to extend the emission wavelength of Si-based MOS LED to ~1.5 ( an important wavelength for fiber-communication) and ~2 . The origin of the ~1.5 emission is due to the radiative recombination between the electrons and holes confined in the SiGe QD and the ~2 light emission is due to the recombination of holes on the valence bandedge of the Ge quantum well and the electrons on the conduction bandedge of the Si cap. The tensile strain effect of these two kinds of MOS LEDs was also investigated from EL spectra data. In addition, the emission peak of 20-layer SiGe QDs sample is observed 16 meV higher than that of 5-layer SiGe QDs sample due to more relaxation during growth.
Subjects
穿隧二極體
tunneling diodes
Type
thesis
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