Ge/Si(001) Heterostructures with Quantum Dots: Formation, Defects, Photo-Electromotive Force and Terahertz Conductivity

Issues of Ge hut cluster nucleation and growth at low temperatures on the Ge/Si(001) wetting layer are discussed on the basis of explorations performed by high resolution STM and in-situ RHEED. Data of HRTEM investigations of Ge/Si heterostructures are presented with the focus on low-temperature formation of perfect multilayer films. Exploration of the photovoltaic effect in Si p--i--n-structures with Ge quantum dots allowed us to propose a new approach to designing of infrared detectors. First data on THz dynamical conductivity of Ge/Si(001) heterostructures in the temperature interval from 5 to 300 K and magnetic fields up to 6 T are reported.