Quantum effects in semiconductor components

The importance of quantum phenomena in semiconductor components, in particular in Si MOSFETs and GaAlAs/ GaAs heterostructures, is outlined. A short theoretical description of quantization effects in surface potential wells and at high magnetic fields is given. Multiple quantum well structures and modulation-doped heterostructures, as well as their possible applications are described. The discovery of the quantum Hall effect (QHE) is shown to be a result of the development of high-quality components. The features and the importance of the QHE for basic physics are outlined. Recent experimental data are discussed showing that the theoretical description of QHE is still unsatisfactory. A possible analogy of QHE to some features of superconductivity based on the idea of a changed effective mass is considered.