The excitation and decay mechanisms of the Yb3+ intra-4f-shell emission are studied in n-type Mow-grown and p-type LPE grown InP:Yb layers by photoconductivity measurements, time-resolved photoluminescence, photoluminescence excitation and emission spectroscopy. Assuming a pseudodonor or pseudo-acceptor-like character of the isoelectronic Yb3+ T,, centre the temperature dependences of the 41-shell transition intensity and lifetime can be consistently explained. Models for the excitation and decay processes of the Yb3+ photoluminescence are proposed.

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Optical and electrical measurements of GaAs layers grown by liquid phase epitaxy with different amounts of Yb metal (0–1000 ppm) added to the Ga solution are reported. The presence of Yb during growth causes strong suppression of all donor-related optical transitions due to the effective removal of donors, as judged from Hall effect data. We have not found any appreciable increase of the background acceptor concentration during conductivity conversion from n-type to p-type, and thus conclude that dominant donor gettering occurs already in the Ga solution. No Yb3+ (4f 13)-related emission was detected in the as-grown GaAs layers.

Optically detected microwave-induced impact ionization of excitons and shallow donors is studied in Yb-doped InP grown by metalorganic chemical vapor deposition. The experimental results directly confirm that Yb3+ intrashell emission is induced by nonradiative recombination of Yb bound excitons due to an impurity Auger effect. Yb3+ ions in InP are found to bind excitons with the electron being localized first, followed by subsequent hole capture.