PRESSURE-INDUCED INTRA-4F LUMINESCENCE IN GAAS-ER,O

In metalorganic chemical vapor deposition grown GaAs:Er,O samples, at ambient pressure, only the Er-Ca-20 center is excited by above band ga p host photoexcitation (host excitation) and shows a sharp infrared lu minescence spectra due to intra-4f transitions in the Er3+ ion. It is found, at high pressure, that at least two other Er centers become opt ically active by host excitation. One of these pressure-induced center s is assigned to a specific Er center having slightly different atomic configuration than the Er-Ca-20 center by comparing the pressure-indu ced photoluminescence (PL) spectra with the site-selective PL spectra. (C) 1997 American Institute of Physics.