Density-of-states tails associated with the <100> conduction band minima in heavily doped n-type GaAs

In contrast with the photoluminescence of lightly doped n-type GaAs, a reduction in the temperature of heavily doped material produced an intensification and a broadening of the spectrum on the high-energy side of the band gap. This effect is attributed to the presence of 'density-of-states' tails associated with the indirect <100> minima in the conduction band of the heavily doped material.