For the first time observed self-assembling nanohills induced by irradiation of nanosecond Nd:YAG laser pulses (pulse duration 15 ns; wavelength 1062 nm; power 1MW) in the SiGe/Si heteroepitaxial structures with initially uniform distribution of Ge atoms over the top layer is reported. The Photoluminescence band at 700-800 nm the maximum of which shifting to shorter wavelengths with the increase of the intensity of laser radiation and appearance of the 300 cm-1 Ge-Ge vibration band in micro-Raman spectra are explained by the Quantum confinement effect in nanohills. An AFM study of the morphology of irradiated surface has shown formation of particularly-oriented nanohills after laser irradiation of the intensity 32 MW/cm2. Ellipsometry data confirmed appearance of Ge-rich phase precipitates amounting to 4.6% and 2.1% of the total Ge content induced by laser radiation of intensities 32 MW/cm2 and 25 MW/cm2, respectively. Formation of the Ge-rich phase is explained by localization of Ge atoms drifting toward the irradiated surface under the thermal gradient due to strong absorption of the laser radiation.