Fabrication Of Quantum Wire Structures Research Articles

Highly anisotropic morphologies of GaAs(331) surfaces

The surface morphology of the GaAs(331) surface was investigated by in situ reflection high-energy electron diffraction and scanning tunneling microscopy. It was found, that GaAs(331) A and B surfaces are both faceted on a nanometer scale, containing (110) and (111) facets which are atomically resolved in real space. The resulting highly anisotropic ridge-like surfaces can prove useful in the fabrication of quantum wire structures.

A theoretical analysis of quantum-wire fabrication by vacancy-enhanced interdiffusion of quantum wells

The fabrication of quantum-wire structures using vacancy enhanced interdiffusion of quantum wells is analyzed theoretically. A phenomenological equation is used to describe the effects of strain on vacancy diffusion. The quantum-wire confinement potentials are studied as a function of the trench opening widths and the separation distances from the SiO/sub 2/-AlGaAs interface. The lateral confinement energy is not a monotonic function of the trench opening width. It first increases and then decreases when the trench opening width is decreased. When the separation distance of the quantum wire from the interface is reduced, the confinement potential is changed from a nonsquare profile to a square-well profile.

The fabrication of quantum wire structures through application of CCl4 towards lateral growth rate control of GaAs on patterned GaAs substrates

We have observed the remarkable increase of GaAs lateral growth rate in the presence of CCl4 during metalorganic chemical vapor deposition (MOCVD) on patterned GaAs substrates. The lateral growth rate shows a linear dependence on CCl4 flow rate. On the other hand, the GaAs vertical growth rate is relatively insensitive to the CCl4 flow rate. The maximum ratio of lateral to vertical growth rate is about 14. Using these characteristics, we have fabricated CCl4-doped quantum wires (QWRs) on V-groove structures. The QWR structures show thickness enhancement factors, defined as the ratio of QWR thickness in the center region to the quantum well thickness in the nonpatterned region, as high as 5.6.

Fabrication of quantum wire structures by in-situ gas etching and selective-area metalorganic vapor phase epitaxy regrowth

GaAs quantum wires (QWIs) buried on a V-shaped groove were successfully fabricated by the selective-area in-situ gas etching and regrowth processes in the metalorganic vapor phase epitaxy (MOVPE) reactor. The V-shaped groove formation by in-situ HCl gas etching and the behavior of selective growth in the V-groove were investigated. From the detail study, it was found that the AlGaAs-based quantum wires for the entire range of Al composition can be fabricated by the in-situ fabrication technique with high controllability. Clear photoluminescence peak from an arrowhead-shaped GaAs QWI completely surrounded by Al 0.5Ga 0.5As was obtained even at room temperature, indicating that the in-situ etching/regrowth processes are a very promising technique for realizing high performance nanostructure devices such as QWIs.

Making quantum wires and boxes for optoelectronic devices

Abstract This paper will review current techniques used to fabricate low dimensional quantum structures for optoelectronic applications. Work has included the fabrication of quantum wire structures using molecular beam epitaxy (MBE) growth of tilted superlattices on vicinal substrates, observation and modeling of self-ordering effects that occur during this process, extension to antimony-containing III–V compounds, and quantum wire formation in “serpentine superlattices”. In addition, we will discuss results obtained using focused ion beam implantation techniques to “write” quantum wires and boxes. Direct growth by both MBE and metal-organic chemical vapor deposition (MOCVD) on lithographically patterned substrates, presently underway at Bellcore, will also be described, along with the electron-beam patterning and MOCVD regrowth of phosphide-based quantum wire and box configurations carried out at the Tokyo Institute of Technology. Application of these various fabrication techniques to semiconductor lasers and high-speed photodetectors will be discussed.