| Summary: | 碩士 === 國立中央大學 === 物理研究所 === 99 === In this paper, we have studied the optical properties of Ge/Si/Ge quantum dots (QDs) structure by using Photoluminescence (PL) spectroscopy.And we use rapid thermal annealing process to improve its light efficiency.Comparing the PL measurements of Ge/Si/Ge QDs structure with Ge/Si QDs structure, the structural difference effect on optical properties is studied.
According to the emission energy of annealed samples in excitation-powerdependent PL measurements, we found that Ge/Si/Ge QDs structure has higher emission energy and lower carriers confinement depth due to atomic intermixing
effect. According to the PL intensity with power sublinear relation at different temperature measurements, we suggest that the defect has negative effect on light efficiency because emitting light will be absorbed by the electrons confined in the defect. Finally, we found that the Ge/Si/Ge QDs structure has higher activation energy from Temperature-dependent PL measurements. Therefore, we
point out that the holes in Ge/Si/Ge QDs structure probably can exist on nearby QDs by tunneling effect.
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