ANTSY - Assembly for Nanotechnology Survey Courses
Closed Systems – Electronic States
Quantum Dot Lab
Individual quantum dots can be created from two-dimensional electron or hole gases present in remotely doped quantum wells or semiconductor heterostructures. The sample surface is coated with a thin layer of resist. A lateral pattern is then defined in the resist by electron beam lithography. This pattern can be transferred to the electron or hole gas by etching or by depositing metal electrodes (lift-off process) that allow the application of external voltages between the electron gas and the electrodes. Such quantum dots are mainly of interest for experiments and applications involving electron or hole transport, i.e., an electrical current. The energy spectrum of a quantum dot can be engineered by controlling the geometrical size, shape, and strength of the confinement potential. Also, in contrast to atoms, it is relatively easy to connect quantum dots to conducting leads using tunnel barriers, which allows the application of the techniques of tunneling spectroscopy for their investigation. Confinement in quantum dots can also arise from electrostatic potentials (generated by external electrodes, doping, strain, or impurities).
Quantum Dot Lab in ANTSY computes the eigenstates of a particle in a box of various shapes, including domes and pyramids.
Lectures and Exercises:
- A lecture in flash and pdf starts from particle-wave duality and explores the concepts of quantum dots.
- Introduction to Quantum Dot Lab is a lecture with exercises in flash and pdf form.
Exercises: