InGaN/GaN Quantum Dots --- Growth, Nano-Structure Material Analysis, and Optical Characterization.

摘要

We compare the result of strain state analysis (SSA) and photoluminescence (PL) of six InGaN/Gan quantam well samples with un-doped, well-doped, and barrier-doped structures. Based on SSA images,a strain relaxation model is proposed for describung the nanostructure differences between the three sets of sample of different doping conditions. In the barrier- doped samples, the hetero-structure- induced.Therefore, strongly clustering nanostructures (quantum dots) are observed. In the well-doped samples, strain are partially relaxed and the spinodal decompositions are observed. Then, in the Un-doped samples,the un-relaxed strains result in higher miscibility between InN and GaN,Leading to the relatively more uniform composition distributions. Between the Low- and high-indium samples, higher indium content leads toa stronger clustering behavior. The strain relaxations in the well- doped and barrier-doped samples result in their unclear S-Shape behaviors of PL spectral peaks. The enhaused carrier localization and reduced quantum-confined stark effect in the barrier-doped samples are responsible for their significant increases of radiative efficiency.