Effect of Rapid Thermal Annealing on the Ripening Mechanism of ZnTe/ZnCdSe Quantum Dots Grown by Molecular Beam Epitaxy

• Main Authors: Hung, Yi-Ting, 洪翊庭
• Other Authors: Chou, Wu-Ching
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/6jv52d

碩士 === 國立交通大學 === 電子物理系所 === 105 === In this work, ZnTe/ZnCdSe quantum dots sample were grown on GaAs (001) substrate with ZnSe buffer layer by molecular beam epitaxy (MBE). Photoluminescence (PL), temperature-dependent PL (TDPL), and time-resolved PL (TRPL) were used to investigate the optical properties of rapid thermal annealed samples. For annealed 3.2 MLs ZnTe/Zn0.88Cd0.12Se quantum dots, the PL peak position exhibited a redshift resulted from the ripening effect. On the other hand, TRPL spectrum showed that the carrier lifetime of the ripened sample decreased as the average dot size became larger. However, there was no obvious PL energy shift in annealed ZnTe/Zn0.78Cd0.22Se quantum dots. It could be more difficult to form quantum dots because the lattice mismatch between ZnTe and Zn1-xCdxSe decreased as the Cd composition (x) increasing from 0.12 to 0.22. As a result , the reduced dot density suppressed the ripening effect. We demonstrated that the rapid thermal annealing can be used to control the dot size and uniformity of high density ZnTe/ZnCdSe quantum dots.