C.L. Zhang

Growth of nanostructures on composition-modulated InAlAs surfaces

InAs self-organized nanostructures were grown with variant deposition thickness and growth rate on closely matched InAlAs/InP by molecular-beam epitaxy. The structural properties of InAs and InAlAs layer were studied. It is found that the InAs morphology is insensitive to the growth conditions. Transmission electron microscopy and reflectance difference spectroscopy measurements show that the InAlAs matrix presents lateral composition modulation which gives birth to surface anisotropy. Based on the dependence of the InAs morphology on the anisotropy of the InAlAs layer, a modified Stranski–Krastanow growth mode is presented to describe the growth of the nanostructure on a composition-modulated surface.

Site controlling of InAs quantum wires on cleaved edges of AlGaAs/GaAs superlattices

Site-controlled InAs quantum wires were fabricated on cleaved edges of AlGaAs/GaAs superlattices (SLs) by solid source molecular beam epitaxy. The cleaved edge of AlGaAs/GaAs SLs acted as a nanopattern for selective overgrowth after selective etching. By just growing 2.0 ML InAs without high temperature degassing, site-controlled InAs quantum wires were fabricated on the cleaved edge. Furthermore, atomic force microscopy demonstrates the diffusion of In atoms is strong toward the [00 (1) over bar] direction on the (110) surface.

Controlled growth of III-V compound semiconductor nano-structures and their application in quantum-devices

Various techniques on the growth of self-assembled compound semiconductor nano-structures (quantum dots, QDs) have been tried to enhance the controlling on size, density, emitting wavelength, uniformity in size and ordering in location of the QDs. Optimized growth conditions have been used in the application of the QD materials in opto-electronic devices. High-power, long-lifetime quantum-dot laser-diodes (QD-LDs) emitting near 1 /spl mu/m, QD-LDs emitting in red-light range, 1.3 /spl mu/m QD-LDs on GaAs substrate and quantum-dot super-luminescent diodes (QD-SLDs) have successfully been achieved.

Molecular-beam epitaxial growth of position controlled InAs islands on clean edge of InGaAs/GaAs superlattice

A promising approach for positioning of InAs islands on [110]GaAs is demonstrated. By combining self-assembly of quantum dots with solid source molecular beam epitaxy (MBE) on cleaved edge of InGaAs/GaAs superlattice (SL), linear alignment of InAs islands on the InGaAs strain layers have been fabricated. The cleaved edge of InGaAs/GaAs SL acts as strain nanopattern for InAs selective growth. Indium atoms incident on the surface will preferentially migrate to InGaAs regions where favorable bonding sites are available. The strain nanopatterns effect is studied by the different indium fraction and thickness of In/sub x/Ga/sub 1-x/As/GaAs SL. The ordering of the InAs islands is found to depend on the properties of the underlying InGaAs strain layers.