Self-assembled growth and optical properties of ZnTe/ZnCdSe quantum dots

• Main Authors: Dai, Yue-Ru, 戴悅如
• Other Authors: Chou, Wu-Ching
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/40357552116816203909

碩士 === 國立交通大學 === 電子物理系所 === 102 === In this work, ZnCdSe thin films and the type-II self-assembled ZnTe/ZnCdSe quantum dots (QDs) were grown by molecular beam epitaxy (MBE). The photoluminescence (PL), temperature dependent PL, and the time-resolved PL were used to investigate the optical properties and the carrier relaxation dynamics. By optimizing the growth parameters, the beam equivalent pressure (BEP) of the Zn, Cd and Se cell, high quality ZnCdSe epilayers with controllable Cd composition could be achieved to adjust the energy band gap and lattice constant. For the ZnTe/ZnCdSe QDs, the peak energies of the photoluminescence (PL) spectra show a decrease with the increasing ZnTe coverage. An abrupt variation with coverage was observed, which implies the existence of wetting layer of 3.2 MLs. A significant blue-shift of PL peak energy with the excitation power was investigated due to the carrier-induced band-bending effect, which is a signature of type-II band alignment.