This paper reviews basic research and technical developments on silicon (Si) light-emitting diodes (Si-LEDs) fabricated by using a novel dressed-photon-phonon (DPP)-assisted annealing method. These devices exhibit unique light emission spectral profiles in the wavelength range 900-2500 nm, including novel photon breeding features. The highest optical output power demonstrated was as high as 2.0 W. It is pointed out that boron (B) atoms, serving as p-type dopants, formed pairs whose length was three-times the lattice constant of the host Si crystal. These B atom pairs are the origin of the photon breeding. It is pointed out that photon breeding took place with respect to photon spin. Furthermore, recent measurements show that the B atom pairs tend to form a chain-like configuration.