| Summary: | 碩士 === 國立臺灣大學 === 光電工程學研究所 === 90 === In this thesis, the effects of surface states on the band structure and optical properties of n-type doped indium gallium nitride (InGaN) multiple quantum wells (MQWs) are investigated. Based on a conventional self-consistent analysis of the Schrödinger and Poisson equations, this calculation model incorporating surface states is conducive to solving the band structures of nitride-based MQWs. The two-dimensional electron gas (2DEG) coming from the surface states and intentional dopants congregates the material interfaces to screen the polarization charge. The phenomenon explains the hypothesis of the “periodic boundary condition of electric field” and the “equivalent charge model”. Moreover, the screening amount of polarization charge varies with the Fermi level, the temperature, and the density of injection carriers.
By means of the optical pumping experiment of the InGaN MQW sample, the accuracy of the present model (called the “surface state model”) can be confirmed. The “surface state model” is more accurate than the “equivalent charge model” at the peak energy by comparing with the 300K and 77K PL results. It shows that the linearity between the piezoelectric fields screening and the peak energy shifting plays an important role in optical properties of InGaN MQWs.
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