LARGE BLUESHIFT IN THE PHOTOLUMINESCENCE OF PSEUDOMORPHIC INGAAS GAASQUANTUM-WELLS GROWN IN PATTERNED (100)GAAS GROOVES AND RIDGES WITH VERTICAL SIDEWALLS/

Molecular beam epitaxial growth of pseudomorphic InGaAs quantum wells on (100) GaAs substrates, patterned with vertical sidewalls using reac tive ion etching, were studied. Contrary to the redshift observed in t he photoluminescence from the ridges and grooves of patterned substrat es with (n11) sidewalls, we have observed a blueshift in the case of v ertical sidewalls. The possibilities of change in the strain tensor an d the change in composition of the InGaAs grown in the grooves or on t he ridges were considered in order to explain this increase in band ga p. We believe that the vertical sidewalls act as kink sites for the mi grating adatoms instead of sources, as in the case of (n11) sidewalls. We have demonstrated a blueshift of up to 50 meV without any degradat ion in the intensity and linewidth of the photoluminescence spectra. ( C) 1996 American Vacuum Society.