Controlling Densities of Manganese Ions and Cadmium Vacancies in Cd1鈥?i>xMnxTe Ultrasmall Quantum Dots in a Glass Matrix: x-Concentration and Thermal Annealing

详细信息    查看全文

• 作者：Noelio O. Dantas ; Guilherme L. Fernandes ; Oswaldo Baffa ; Jorge A. G贸mez ; Anielle Christine A. Silva
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 30, 2015
• 年：2015
• 卷：119
• 期：30
• 页码：17416-17420
• 全文大小：391K
• ISSN：1932-7455

文摘

In this work, we used nominal concentration (x) and thermal annealing to control the density of manganese (Mn²⁺) ions and cadmium vacancies (V_Cds) in Cd_1鈥?i>xMn_xTe ultrasmall quantum dots (USQDs) embedded in a glass matrix. The physical properties were investigated by photoluminescence (PL) and electron paramagnetic resonance (EPR). PL bands related to surface defects and Mn²⁺ ions intensified, whereas bands related to V_Cds decreased with increasing manganese concentration. Longer thermal annealing times caused decreases in the intensity of PL bands characteristic of Mn²⁺ ions and V_Cds. The EPR spectra confirmed that manganese exhibited +2 oxidation states and was incorporated at the core and surface of the Cd_1鈥?i>xMn_xTe USQDs. Furthermore, the quantities of Mn²⁺ ions within the Cd_1鈥?i>xMn_xTe USQDs confirmed that longer thermal annealing times were associated with constant diffusion of these ions from the core to the surface and then the glass. Therefore, we demonstrated that longer thermal annealing times and higher manganese concentrations make it possible to control both the emissions intensities related to V_Cds and Mn²⁺ ions and the diffusion of these ions to the surface and then the glass.