Transmission Electron Microscopy Studies of InGaN/GaN Multiple Quantum Well Nano-Structures of Different Silicon Doping Conditions
Date Issued
2004
Date
2004
Author(s)
Chen, Meng-Ku
DOI
en-US
Abstract
In this research, we have investigated the nanostructures of
InGaN/GaN multiple quantum wells (MQWs) with different indium concentrations, different silicon doping regions, and different silicon doping concentrations. We also studied the effects of post-growth thermal annealing and electron beam exposure on the nanostructure. The methods
used for studying our samples, including material and optical analysis methods. Material analysis methods include high-resolution transmission electron microscopy (HRTEM) and the strain-state analysis (SSA). Optical analysis methods include photoluminescence (PL) and photoluminescence excitation (PLE). From strain-state analysis (SSA) results, we could clearly see the differences of nanostructures between the samples of different doping conditions. Typically, more clusters were
formed in Si-doped samples, particularly in the barrier-doped sample. Also, more clusters can be formed by increasing silicon doping concentration. Optical measurements showed that with Si-doping, the recombination efficiency could be improved. Such an improvement could
be attributed to stronger carrier localization (more clusters formed) and better strain relaxation (weaker quantum-confined stark effect) upon silicon doping, particularly doping in barriers. We have observed that
thermal annealing could change the nanostructures and optical properties of InGaN/GaN MQWs. We have found that electron beam exposure for a few minutes may not change the nano-structure of an InGaN/GaN QW sample.
Subjects
量子井
氮化銦鎵
氮化鎵
quantum well
GaN
InGaN
Type
thesis
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