PHOTOLUMINESCENCE STUDY OF RARE-EARTH-DOPED SEMICONDUCTORS UNDER PRESSURE

High pressure photoluminescence (PL) studies are reported for InP:Yb a nd GaAs:Er, O. In InP:Yb; the thermally quenched intra-4f luminescence is recovered bg applying pressure near room temperature. Simultaneous ly the band-edge related emission decreases. This result is interprete d qualitatively by a thermal equilibrium between the photocreated elec tron-hole pair of the host InP and the excited state of the 4f shell. In MOCVD grown GaAs:Er, O, the sharp luminescence from tile intra-4f t ransition of Er is observed at 1.538 mu m at atmospheric pressure. Thi s is the main emission associated with the Er-Ga-2O center which has C -2v symmetry. For increasing pressure tile PL intensity of the Er intr a-4f emission increases and also some new PL lines appear at low tempe ratures. These pressure-induced new lines are assigned to other Er cen ters with different atomic configurations.