We studied infrared photoluminescence in wire-like silicon crystals grown by gold stimulated CVD technique. Such crystals present the smallest Si-based heterostructure consisting of bulk silicon and a cell-assembled silicon envelope. Cells have spheroid-like shape. Size of the cells equals 2-5 nm. A thickness their fact walls is equal to ~ 1 nm. A complex structure of the crystals gives rise to a complex photoluminescence spectra consisting of the know spectra of bulk silicon ( band-exciton and LO- and TO-replicas) and intensive new band at 1,139 eV. The larger is a thickness of the envelope the more intensive new band.
We studied a spectral shape of the new band and its intensity versus a power exciting and temperature. It was found that both they differ completely from the known spectra of bulk silicon and indicate on quantum origin of the envelope and on existence of superradiance.