Type-II Quantum Dots: CdTe/CdSe(Core/Shell) and CdSe/ZnTe(Core/Shell) Heterostructures

作者：Sungjee Kim, Brent R. Fisher, Hans‐Jürgen Eisler, Moungi G. Bawendi · 发表于：Journal of the American Chemical Society · 年份：2003 · DOI：10.1021/ja0361749 · 被引用次数：1302 · 研究领域：Quantum Dots Synthesis And Properties、Chalcogenide Semiconductor Thin Films、Semiconductor Quantum Structures and Devices

Type-II band engineered quantum dots (CdTe/CdSe(core/shell) and CdSe/ZnTe(core/shell) heterostructures) are described. The optical properties of these type-II quantum dots are studied in parallel with their type-I counterparts. We demonstrate that the spatial distribution of carriers can be controlled within the type-II quantum dots, which makes their properties strongly governed by the band offset of the comprising materials. This allows access to optical transition energies that are not restricted to band gap energies. The type-II quantum dots reported here can emit at lower energies than the band gaps of comprising materials. The type-II emission can be tailored by the shell thickness as well as the core size. The enhanced control over carrier distribution afforded by these type-II materials may prove useful for many applications, such as photovoltaics and photoconduction devices.