Determination of band gap narrowing and hole density for heavily C‐doped GaAs by photoluminescence spectroscopy

The energy band gap narrowing effect in heavily C‐doped GaAs was investigated using photoluminescence spectroscopy. The band gap was determined over the hole density range 1017–4×1020 cm−3 at 10 and 300 K. The band gap data at low temperatures confirm the available theoretical calculations up to 1020 cm−3. An unexpected temperature dependence of the observed band gap at high doping levels is discussed on the basis of carrier‐phonon interactions. We present an analysis of the band gap narrowing effect that can be used for nondestructive measurement of hole densities in the range 1017–4×1020 cm−3.