Strained GaxIn1−xP multiple quantum wire light-emitting diodes: A luminescence polarization study

Abstract

Strongly polarized photoluminescence and electroluminescence spectra have been obtained from strained GaxIn1−xP quantum wire heterostructures grown on (100) oriented, on-axis GaAs substrates by an in situ epitaxial technique. The phenomenon of strain-induced lateral layer ordering has been exploited in order to create lateral superlattices of GaxIn1−xP compositionally modulated in the [110] direction with a modulation period of 96 Å. The previous and subsequent growth of lattice-matched Ga0.51In0.49P ternary alloy epilayers results in the formation of compressively strained quantum wires. Transmission electron microscopy shows the wire cross sections to be ∼48×200 Å. These structures exhibit 77 K photoluminescence spectra at 1.79 eV that are strongly (96%) polarized parallel to the wires due to strain resulting from the lateral compositional modulation. The intensity of this emission depends critically on the polarization of the incident excitation. Electroluminescence spectra from multiple quantum wire light-emitting diodes display anisotropic polarization as well. The energies and optical anisotropies of these luminescence bands are consistent with a simple theoretical analysis.

Polarization anisotropy in room temperature contactless electroreflectance spectrum of self-organized lateral compositional superlattices

“…The cause of this composition modulation is still not well understood [1]. Transmission electron microscopy (TEM), energy-dispersed X-ray analysis (EDX) and polarized photoluminescence (PL) results have been put forth as evidence for the occurrence of composition modulation [3][4][5]. There is considerable interest in establishing the electronic band structure changes due to this composition modulation.…”

Time-resolved cathodoluminescence study of carrier relaxation in strained (InP)2/(GaP)2 quantum wires

“…5-9 A lateral modulation of the In and Ga compositions, by as much as ϳ30%, has been observed in transmission electron microscopy ͑TEM͒ and energy dispersive x-ray spectroscopy ͑EDS͒ studies. 6,7 Nonlinear optical properties in such structure are expected to be enhanced due to the narrowing of the DOS in a two-dimensionally confined system. One important nonlinear optical property is the change in the emission of light ͑in energy, polarization, and intensity͒ that results from phasespace filling of carriers.…”

Two-dimensional array of self-assembled AlInAs quantum wires

“…Attempts to gain control over the characteristics of these structures led to a better understanding of the surface kinetics during epitaxial growth and, as a result, new and more complex laterally defined structures like lateral superlattices, 1 tilted superlattices, 2 superlattices of dots, 3 arrays of quantum wires, 4 and arrays of quantum pillars 5 have been achieved. However, just as for their predecessors, these structures also suffer from a lack of spatial uniformity thereby impeding the study of their electronic properties.…”