Device quality submicron arrays of stacked sidewall quantum wires on patterned GaAs (311)A substrates

Abstract

Three-dimensional arrays of vertically stacked sidewall quantum wires are fabricated by molecular beam epitaxy on GaAs (311)A substrates patterned with 500-nm-pitch gratings. The cathodoluminescence spectra at low temperature are dominated by the emission from the quantum wires with narrow linewidth accompanied by a very weak emission from the connecting thin quantum wells due to localization of excitons at random interface fluctuations. When the carriers in the quantum well become delocalized at elevated temperature, only the strong emission from the quantum-wire array is observed revealing perfect carrier capture into the quantum wires without detectable thermal repopulation of the quantum well up to room temperature. Thus, unpreceded device quality of this quantum-wire structure is demonstrated.

Atomic Hydrogen Induced Step Bunching on High-Index GaAs Substrates for Fabrication of Novel Quantum Wire and Quantum Dot Arrays by Molecular Beam Epitaxy

“…The existence of uniform quantum-dot arrays manifests itself in the micro-photoluminescence (PL) spectra taken from the sidewall. Like the sidewall quantum wires grown by conventional MBE, 12,13) the micro-PL spectra show emission at higher energy from the corrugated quantum well close to the sidewall and emission shifted to lower energy from the thicker GaAs region along the sidewall. 9) Unlike the emission from the quantum well, which splits up into a series of sharp peaks uniformly distributed over the envelope, the energy range of the sharp line emission from the dot array is strongly reduced.…”

“…Due to the unfacetted and very smooth, convex surface profile achieved by this novel growth mechanism, very uniform, quasi-planar GaAs/(Al, Ga)As sidewall quantum wires with excellent optical properties have been realized. 12,13) In addition, more complex surface patterns, e.g., periodic hole arrays and zigzag sidewalls have allowed fabrication of novel dotlike nanostructures as well as coupled wire-dot arrays. 14) A new quality in nanostructure formation is now opened by combining atomic hydrogen induced periodic step bunching with growth on patterned substrates.…”

“…This direction of the multiatomic step arrays is perpendicular to the fast growing shallow [01−1] oriented mesa sidewall in conventional MBE on patterned GaAs (311)A substrates 11) which has proven a high flexibility for the formation of single and multiple quantum wires, isolated dot-like nanostructures as well as coupled wire-dot arrays. [12][13][14] Hence, the combination of atomic hy-drogen induced self-faceting with patterned growth opens a new dimension in nanostructure formation by transforming sidewall quantum wires to dense linear arrays of quantum dots which exhibit minimized size fluctuations. 9) Figure 1 shows the atomic force microscopy (AFM) top views of the GaAs layers grown at different substrate tem- The growth rate of the 0.25 µm thick GaAs layers was 0.2 µm/h.…”

Electronic and optical properties of [N11] grown nanostructures

“…High quality side-wall InGaAs/AlGaAs QWRs were observed by means of atomic force microscopy [23,24].…”

Highly strained quantum structures grown on GaAs (001) vicinal substrate by MOCVD

“…One of the growth processes, which involve strain-induced lateral ordering (SILO) [3], results in the formation of QWRs with a periodicity of about 15-20 nm. In addition, other attempts such as growing latticematched materials on vicinal substrate, for example, GaAs or GaAs/AlAs QWRs grown on vicinal GaAs substrate of (1 1 0) [4], (3 1 1) A [5], and (7 7 5) B [6] surface by MOCVD or MBE, and InGaAs/GaAs lateral superlattice grown on vicinal GaAs substrate of (1 1 1) A by atomic layer epitaxy [7], have been demonstrated.…”