E. Neufeld et al., INFLUENCE OF GERMANIUM CONTENT ON THE PHOTOLUMINESCENCE OF ERBIUM-DOPED AND OXYGEN-DOPED SIGE GROWN BY MOLECULAR-BEAM EPITAXY, Applied physics letters, 71(21), 1997, pp. 3129-3131
The photoluminescence at 1.54 mu m of erbium-and oxygen-doped Si/Si1-x
Gex samples grown completely by molecular beam epitaxy has been invest
igated for germanium concentrations ranging from x = 0 to x = 0.165. T
he dopants were either placed into the Si1-xGex or into the Si layers
of an alternating Si/Si1-xGex layer structure. Because of the good cry
stal quality after growth, it was possible to obtain all luminescence
data from as-grown samples without annealing. We observed a decrease i
n photoluminescence (PL) intensity and a stronger temperature dependen
ce with increasing Ge content. For samples with the same Si/Si1-xGex l
ayer structure, an enhancement of PL intensity at low temperature was
seen when erbium and oxygen were placed into the Si1-xGex layers rathe
r than into the Si layers. We attribute this effect to a capture of ph
otogenerated carriers in the Si1-xGex layers. (C) 1997 American Instit
ute of Physics.