Dynamical localization effect in a coupled quantum dot array driven by an AC magnetic field

We have studied the transport properties of a ring-coupled quantum dot array driven by an AC magnetic field, which is connected to two leads, and we give the response of the transport current to the dynamical localization. We found that when the ratio of the magnetic flux to the total quantum dots number is a root of the zeroth order Bessel function, dynamical localization and collapse of quasi-energy occurs and importantly~ the transport current displays a dip which is the signal of dynamical localization. The dynamical localization effect is strengthened as a result of the increase of the quantum dot number, and it is weakened on account of the increase of the dots-lead hopping rate.

Simplified modeling of frequency behavior in photonic crystal vertical cavity surface emitting laser with tunnel injection quantum dot in active region

In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.

One-bath synthesis of hydrophilic molecularly imprinted quantum dots for selective recognition of chlorophenol

A simple one-bath strategy has been developed to synthesize a novel CdTe@SiO_2@MIP（molecularly imprinted and silica-functionalized CdTe quantum dots,MISFQDs）,in which a silica shell was coated on the surface of CdTe quantum dots （CdTe@SiO_2 QDs） and then a polymer for selective recognition of 4-chlorophenol（4-CP） was constructed on the surface of CdTe@SiO_2 QDs using mercaptoacetic acid as stabilizer,3-aminopropyl-trimethoxysilane（APTES） as functional monomers and tetraethoxysilane（TEOS） as crosslink agent.The structures of CdTe@SiO_2@MIP were analyzed by ultraviolet-visible absorption. Fluorescence,FT-IR spectrum and powder X-ray diffraction.The application and characterization of the CdTe@SiO_2@MIP were investigated by experiments.All results indicated that the CdTe@SiO_2@MIP can selectively recognize 4-chlorophenol.

Synthesis of bovine serum albumin imprinted Mn:ZnS quantum dots

A novel bovine serum albumin （BSA） imprinted Mn-doped ZnS quantum dots （Mn：ZnS QDs） is firstly reported. The molecular imprinted polymer （MIP） functionalized Mn：ZnS QDs （Mn：ZnS @SiO2@MIP） include the preparation of Mn：ZnS QDs, the coating of silica on the surface of Mn：ZnS QDs, and the functional polymerization by sol-gel reaction using 3-aminophenylboronic acid as the functional and cross-linking monomer in the presence of BSA （Mn：ZnS@SiO2@MIP-BSA）, and then the elution of the imprinted BSA on the surface of Mn：ZnS@SiO2 QDs. The results showed that the phosphorescence of Mn：ZnS@SiO2@MIP is stronger quenched by BSA than that of non-imprinted one （Mn：ZnS@SiO2@NIP）, indicating that the selectivity of the imprinted Mn：ZnS quantum dots toward BSA is superior to that of non-imprinted one.