InGaAs layer effect on the growth of AlGaAs/GaAs quantum wires on V-grooved GaAs substrates

We have studied an effect of InGaAs layer on the structural and optical properties of AlGaAs/GaAs quantum wires (QWRS) grown on V-grooved GaAs(100) substrates by metalorganic chemical vapor deposition. The In,,Ga,s,As layer with thickness of 2-4 /*rn were prepared on GaAs(100) substrates, and the V-grooves were defined with 20 pm intervals by photolithographic method. The quantum structures with five periods of 5 nm GaAs and 25 nm A1,,Ga,SAs layers were grown on V-grooved InGaAs/GaAs substrates. From the scanning electron microscope and transmission electron microscope measurements, it appeared that the thick InGaAs layer caused to form several facets in the side walls of V-grooves. Especially, the side walls near the bottom were convexly shaped, resulting in narrowing the width near the bottom of the V-groove. In the photoluminescence (PL) spectra, QWRs grown on this substrate showed a blue shift, while any PL signal from the top-quantum wells on InGaAs layer has not appeared. From these results, it was suggested that the InGaAs layer plays an important role for the lateral tightening of QWRs.