Lab #8 Quantum Dots Experiment


Conceptual goal: Learn about a system whose properties can only be explained by using quantum mechanics. Relate the size-dependent band gap of the quantum dots to their emission spectra.
Experimental goal: Use of a spectrometer to record intensity vs. wavelength for four different vials. Compare the spectra obtained and relate results to the different sizes of the quantum dots.

An atomic cluster is a nano-scale system that contains only a few to a few thousand atoms. Much research is currently being done on atomic clusters, as it was discovered that, because of quantum confinement, their properties (for example, at what wavelengths they absorb or emit light) can be size dependent. It is thus possible to tailor these properties, which might lead to new technological applications. For the experimental portion of this laboratory, we have adapted the handout that accompanies CENCO Quantum Particles in a Box. and we use Ocean Optics spectrometers. Students learn how to use a spectrometer to record emission data for a set of quantum dots, and how to relate the peak emission wavelength to the semiconductor’s gap by modeling the dots as semiconductor spheres with a particle and a “hole” (the absence of an electron).

This material is based upon work supported by the National Science Foundation under Grant Number DUE-1140034.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.