Self-assembled Semiconductor Quantum Dots Research Articles

Spatially Resolved Visible Luminescence of Self-Assembled Semiconductor Quantum Dots

Ensembles of defect-free InAIAs islands of ultrasmall dimensions embedded in AIGaAs have been grown by molecular beam epitaxy. Cathodoluminescence was used to directly image the spatial distribution of the quantum dots by mapping their luminescence and to spectrally resolve very sharp peaks from small groups of dots, thus providing experimental verification for the discrete density of states in a zero-dimensional quantum structure. Visible luminescence is produced by different nominal compositions of InxAI(1-x)As-AIyGa(1-y)As.

Novel coordination complexes of tetrathiafulvalene derivatives

We have been investigating the use of tetrathiafulvalene tetrahiolate (1) as a ligand for a variety of new tetrathifulvalene based coordination compounds (2). In the generation of 1, we have found that dithiolates and trithiolates are formed by the incomplete metallation of TTF. Herein is presented a method for the clean generation of 1, the synthesis of a Pt(II) complex and a Ni(II) complex of 1, and the results from the use of 1 as a difunctional bridging ligand in the synthesis of self-assembled CdSe nanocrystalline semiconductor (quantum dot) networks. The resultant TTFS4-quantum dot networks show greatly enhanced luminescence (a 50-fold increase) over the typical butanethiol capped CdSe quantum dots.