Photoluminescence properties of Cu-doped CdTeSe alloyed quantum dots versus laser excitation power and temperature

• Published in: Journal of luminescence 2020-02, Vol.218, p.116838, Article 116838
• Main Authors: Hien, N.T., Tan, P.M., Van, H.T., Lien, V.T.K., Do, P.V., Loan, P.N., Kien, N.T., Luyen, N.T., Ca, N.X.
• Format: Article
• Language: English
• Subjects: Cu–CdTeSe quantum dots; Excitonic and impurity emissions; Optical properties
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2019.116838

Ternary alloy semiconductors have been proven to be suitable host lattices, which could be doped with transition metals (TM) to control the bandgap energy (Eg) and optoelectronic properties. Through many works performed on TM-doped ternary alloys, their photoluminescence (PL) properties versus the laser excitation power (Pex) and temperature (T) have not been investigated in detail. This work presents a careful study on the effect of Pex and T on the PL properties of zinc-blend Cd1-xCuxTe0.5Se0.5 alloyed quantum dots (QDs) with x = 0, 0.005 and 0.05, which were synthesized by a wet chemical method. At T = 300 K and Pex = 0.1 mW, we observed the PL spectra of x = 0 and 0.005 exhibiting two emissions peaked at about 644 and 820 nm associated with near-band-edge excitons (Ehigh) and lattice defects and Cu2+ ions (Elow), respectively. Meanwhile, the PL spectrum of x = 0.05 shows only one emission (Elow) associated with Cu2+ ions. Interestingly, at 300 K, as increasing Pex from 0.1 to 100 mW, we observed the redshift of Ehigh and the blueshift of Elow. If fixing Pex at 0.1 mW, the study of PL spectra in the range of T = 15–300 K indicated that the emission-peak positions of Ehigh(T) and Elow(T) could be described by Varshni's empirical law while their intensity could be described by the Arrhenius law. Physical mechanisms related to these phenomena were also discussed. •Cd1-xCuxTe0.5Se0.5 alloyed QDs were synthesized by a wet chemical method.•The PL properties versus the Pex and T of transition metals-doped alloys QDs have been investigated in detail.•Our work demonstrated the possibility of tuning the PL properties of Cd1-xCuxTeSe QDs in terms of changing x, Pex, and T.