Transport at low electron density in the two-dimensional electron gas of silicon MOSFETs

his thesis contains the result of an experimental study on the transport properties of high quality Si MOSFETs at low temperatures. A metalinsulator transition is found at a critical electron density. The electrons in the inversion layer of a silicon MOSFET are trapped in a potential well at the Si-SiO2 interface. At sufficient low temperature the electrons are only allowed to move parallel to the interface, a two dimensional electron gas is formed. Such two dimensional electron systems (2DES) have extensively been studied for decades, but there is still very fundamental physics to be discovered. One of these, the metal-insulator transition at low electron density is investigated. For this transition it is important to have high quality material at least with a mobility, a measure for the quality, above 1m2/Vs. Besides it is important to have full control over the electron density. The electron density can be adjusted accurately enough with a gatevoltage, an can be calibrated with Shubnikov-de Haas ocillation in the resistivity. ... Zie: Summary.