| Summary: | 碩士 === 國立臺灣大學 === 電子工程學研究所 === 95 === Strained Si/SiGe heterostructure has attracted great attention recently for its application in high speed and optoelectronic devises. However, the basic parameters such as band alignment are still not so clear due to the complexity of the band shifting and splitting as a result of strain effect between Si/SiGe lattice mismatch. For optoelectronic applications, band alignment (type-I and type-II) with different oscillation strength can cause extreme different optical transition efficiency. In this thesis, magneto-luminescence measurement was performed for Si/SiGe multi-quantum wells with different strain distribution. Under magnetic fields, the transitions associated with quantum well begin to shift. From the behavior of energy shifting, two kinds of excitons (type-I and type-II) are observed. Theoretical modeling of the diamagnetic shifting both considering cyclotron energy and Zeeman effect was performed, and the agreement between observation and calculation is quite well. With a proper strain manipulation, it is possible to form type-I band alignment which in principle has larger oscillation strength for more efficient light emission than the type-II alignment.
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