Using the liquid phase epitaxy technique (LPE) Ga0.86In0.14As0.13Sb0.87 layers lattice-matched to (100) Te-GaSb have been deposited, which were intentionally doped with Te and Zn in a wide range. The Raman spectra show that the layers become more defective as the dopant molar fraction is increased. Two main vibrational bands are observed in the Raman spectra centred at 230 and 245 cm-1 that depend strongly on the Te (Zn) molar concentration, which are assigned to the vibrational modes GaAs-like and to (GaSb+InAs)-like mixture. The low-temperature photoluminescence of n (p)-type GaInAsSb was obtained as a function of Te (Zn) concentration added to the melt solution. The photoluminescence was interpreted taking into account nonparabolicity of the conduction (valence) band. It is shown that the band-to-band radiative transition energy can be used to estimate the free carrier concentration in GaInAsSb, for a wide range of doping concentration.