Photoluminescence study of self-assembled GaAs quantum wires on (631)A-oriented GaAs substrates

Abstract

Laser operation at room temperature of self-organized In 0.1 Ga 0.9 As/(GaAs) 6 (AlAs) 1 quantum wires grown on (775)B-oriented GaAs substrates by molecular beam epitaxyThe authors report a low-temperature photoluminescence (PL) study of multiple GaAs layers grown between AlAs(0.6 nm)/GaAs(0.6 nm) short-period superlattice barriers (SLBs) simultaneously grown on both GaAs(631)A and (100) substrates. Five GaAs-layers of different nominal thicknesses (L W , ranging from 12 to 2.4 nm) were grown by molecular beam epitaxy. By using (631)A-oriented substrates a self-organized and highly ordered corrugation is obtained in the growth of the GaAs layers, and at the end of the SLB growth, flat surfaces are found. Whereas, for the (100)-oriented sample, flat interfaces are confirmed after the growth of GaAs and SLB layers. By reducing L W below $3.6 nm in the (631) sample, strong quantum wire (QWR)-like confinement is achieved as deduced from polarized PL spectroscopy where polarization degrees as large as 0.43 are obtained. The PL emission energy of the (631)-QWRs is redshifted, as compared with the transitions of the (100)-oriented quantum wells, when L W is reduced. The authors explain this energy shift by the widening of the effective thickness of the confinement regions in the GaAs layers.

Nanowire Y-junction formation during self-faceting on high-index GaAs substrates

“…This control can be achieved using tactics, such as the structural stress from dissimilar materials to form quantum dots, 1,2 or by growing on high-index substrates to grow uniform one-dimensional facet (1DF) arrays, which are useful as nano-templates to form QWRs. [3][4][5] In MBE the growth process is carried out under non-equilibrium conditions, then nonlinear evolution processes, such as step-bunching, 6 meandering instabilities, 7 and coarsening, 8 produce a very rich variety of surface morphologies, which in turn must be understood to precisely control the self-assembly of complex nanostructures.…”

New orientations in the stereographic triangle for self-assembled faceting

“…[1][2][3][4] Ultra-high-vacuum techniques such as molecular beam epitaxy (MBE) and metalorganic vapor phase epitaxy have been used to grow periodic corrugated structures with remarkable uniformity on surfaces with an unstable high Miller index (HI) or vicinal GaAs substrates (VSs). [5][6][7][8] In addition to its potential for promoting self-assembled structures, epitaxial growth on HI substrates has exhibited many interesting features.…”

“…[5][6][7][8] In addition to its potential for promoting self-assembled structures, epitaxial growth on HI substrates has exhibited many interesting features. For example, HI planes have many characteristics that make them important in basic and applied research, such as the amphoteric nature of Si impurities, 9,10 atypical piezoelectric effects, 11 high degree of light polarization in arrays of quantum wires, 4 observation of anisotropic topological surface states, 12,13 and the enhancement of (In,Ga,Al)P-GaP light-emitting diodes.…”