2Delektronengas

The 2D electron gas, often abbreviated as 2DEG, refers to a system where electrons are confined to move in only two dimensions. This confinement typically arises at the interface between two different semiconductor materials, such as in a metal-oxide-semiconductor field-effect transistor (MOSFET) or in certain heterostructures like gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs). In these structures, an electric field or the difference in material properties creates a potential well that traps electrons, allowing them to move freely in the plane of the interface but preventing motion perpendicular to it.

The properties of a 2DEG are significantly different from those of electrons in bulk materials or in one dimension. Due to the reduced dimensionality, quantum mechanical effects become more pronounced. For instance, the energy levels of the electrons are quantized in the direction perpendicular to the interface, leading to discrete subbands for motion in the plane. This quantization, combined with the high mobility often observed in 2DEGs (meaning electrons can travel long distances without scattering), makes them crucial for advanced electronic devices.

Key phenomena observed in 2DEGs include the quantum Hall effect, where the Hall resistance is quantized in discrete plateaus at low temperatures and strong magnetic fields. This effect is a direct consequence of the energy quantization and the absence of scattering. 2DEGs are fundamental to the operation of many modern electronic devices, including high-speed transistors, sensors, and spintronic devices, and continue to be an active area of research in condensed matter physics and materials science.