Adsorption and Electronic Structure of CdSe Quantum Dots on Single Crystal ZnO: A Basic Study of Quantum Dot-Sensitization System

作者：Toyoda Taro^*; Yindeesuk Witoon; Kamiyama Keita; Hayase Shuzi; Shen Qing^*

来源：Journal of Physical Chemistry C, 2016, 120(30): 16367-16376.

DOI：10.1021/acs.jpcc.6b04130

We describe the morphology and consider the optical absorption and the ground state energy level of CdSe quantum dots (QDs) on single crystal ZnO substrates with various crystal orientations. The morphologies and crystal growth of CdSe QDs were analyzed by atomic force microscopy photoacoustic (PA) spectroscopy for the optical absorption measurements, and photoelectron yield (PY) spectroscopy to evaluate the ground state energy level. The adsorption and crystal growth of CdSe QDs depend on both the adsorption time and the surface orientation of the ZnO substrate. The change in average diameter of the QDs on ZnO with adsorption. time is not related to the crystal surface orientation, and the growth is a two-step process, different from that on single crystal rutile-TiO2. This is characteristic of the difference between CdSe QDs grown on ZnO and those grown on rutile-TiO2. The crystal quality of the QDs on ZnO is poorer than those grown on rutile-TiO2, indicating that the reaction for crystal growth on ZnO is different from that on rutile-TiO2. The energy level of the valence band maximum (VBM) for the (0001) single crystal ZnO surface is higher than those for the (1010) and (1110) surfaces. The ground state energy level of CdSe QDs on single crystal ZnO depend's On both the adsorption time and the surface orientation, which is indicative of the effect of the loss of solvation energy due to the dielectric polarization of the surroundings.

• 出版日期2016-8-4