Electric and photoelectric properties of GaAs/ZnSe–Ge/ZnSe/Al structures with Ge quantum dots

Current-voltage characteristics and spectral dependences of photovoltage are investigated at $T=4.2$ and 300 K in stress-free structures with germanium quantum dots (QDs) in the GaAs/ZnSe/QD–Ge/ZnSe/Al system. The «Coulomb staircase» type features in the current-voltage characteristic observed at room temperature without illumination are due to the Coulomb interaction of electrons in resonant tunneling through intrinsic levels in QDs. The features in the photovoltage spectra are related to the absorption of radiation in the system of discrete levels of QDs. An energy band diagram of the structure is constructed based on the experimental data.