Growth and Optical Properties of CdTe Quantum Dots Grown on ZnSe Buffer Layer by Molecular Beam Epitaxy

• Main Authors: Te-Hsin Chen, 陳德昕
• Other Authors: Jyh-Shyang Wang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/28887363609487350127

碩士 === 中原大學 === 應用物理研究所 === 94 === By molecular beam epitaxy, two groups of CdTe quantum dots were grown on ZnSe buffer layer on GaAs (001) substrates with alternate supplying method. The first group of CdTe quantum dots were grown on Se-stable ZnSe buffer layer and opened Cd effusion cell at first. The second group of CdTe quantum dots were grown on Zn-stable ZnSe buffer layer and opened Zn effusion cell at first. Optical properties were studied by photoluminescence (PL), photoluminescence excitation (PLE), and power dependent photoluminescence. In this study, we found the CdSe and ZnTe precursor layers in the both groups of CdTe quantum dots, respectively. It was corresponded with the growth procedure, and confirmed by the PLE measurements. From the PL measurements, we confirmed that the growth mode of CdTe quantum dots on ZnSe buffer layers was VW mode. However, when the CdTe quantum dot was smaller, because of the superposition of the ground states of quantum dots and the precursor layer, the shape of the PL spectra were asymmetric sharply. On the other hand, as the CdTe quantum dots increased, the PL peak energy decreased while the shape of PL spectra were still a little asymmetric. This is caused by the superposition of the ground state and the excited state of CdTe quantum dots. AFM was also used to confirm the existence of quantum dots. Besides, the power dependent PL was used to confirm the existence of the excited state of quantum dots.