Enhancement of optical nonlinearity in strained (InGa)As sidewall quantum wires on patterned GaAs (311)A substrates

Strong enhancement of the optical nonlinearity occurs in strained (InGa)As sidewall quantum wires grown on patterned GaAs (311)A substrates by molecular beam epitaxy. The wires are formed on the fast growing sidewall of mesa stripes along [01-1] and have a smooth, convex-curved surface profile. The blue shift of the photoluminescence peak energy of the wire in dependence on the excitation power is one order of magnitude larger compared to that of the surrounding well. This enhanced optical nonlinearity is assigned to additional lateral optical band gap modulation due to internal piezoelectric fields effective in the present quantum-wire structure. (C) 1997 American Institute of Physics.