MRSEC Seminar

Toward Confinement Potential Control of Self Assembled Nano Dots

Yossi Paltiel

Applied Physics Department
The Hebrew University, Jerusalem 91904, Israel

Friday, July 31, 4:00 pm

Ryan (Nano) 4003

The ability to grow, and synthesize high quality semiconductor quantum dots (QDs) and QDs based devices was improved tremendously in recent years. In those nano structures it is still possible, in principle, to address single quantum states at high temperature. However, the environment may interfere with the simple isolated quantum states, which one would like to preserve in order to use the quantum properties of the nano devices at room temperature. In our work we aim to understand the relations between the environment and the nano systems.

In self assembled systems, composition, doping, size, and strain distribution within quantum dots, and at the dots-substrate interfaces, determine the confinement potential of electrons and holes creating a complex band structure. Using new non destructive methods like the Coherent Bragg Rod Analysis (COBRA) and Kelvin probe force microscopy we were to map the this confinement potential opening a way to improve the control over the optical properties of the dots.

Lastly, in order to produce a generic methodology for constructing nano-systems in which many devices are interconnected, operate in unison, and are coupled to their macroscopic environment without inhibiting their quantum nature, a new "nano-toolbox" using semiconductor narrow band nanocrystals, metal nano-particles and organic molecules was developed. This system enables using quantum mechanics at room temperature, and may bring about new type of devices such as single photon detectors and emitters, light emitting diodes, IR sensors, solar cells, and photo-electrical devices.

Host: Professor Tamar Seideman, Chemistry