Dependence of the spectral functions near the Fermi level on temperature and rare-earth atom doping was studied in detail for strongly correlated alloys Sm_1−xEu_xB₆ and Yb_1−xLu_xB₁₂ by photoelectron spectroscopy at ≈ 8000 eV as well as at 7 and 8.4 eV. It was found that the 4f lattice coherence and intrinsic gap are robust for Sm_1−xEu_xB₆ at least up to the Eu substitution of x = 0.15 while both collapse by Lu substitution already at x = 0.125 for Yb_1−xLu_xB₁₂. As for the temperature dependence of the spectral shapes near the Fermi level at low temperatures, rather contrasting results were observed between YbB₁₂ and SmB₆. Although the gap shape does not change below 15 K for YbB₁₂ with the characteristic temperature T* of 80 K, the spectral shape of SmB₆ with a T* of 140 K shows that the peak beyond the gap is further increased below 15 K. The temperature dependence of the spectra near the intrinsic gap is clearly different between SmB₆ and YbB₁₂, although both materials have so far been categorized in the same kind of strongly correlated semiconductor. The possibility of the surface contribution is discussed for SmB₆.