UNLABELLED The effect of Sb spray time on the structure of InAs/GaAs quantum dot (QD) systems with Sb spray prior to the capping of a GaAs layer was determined by a Raman scattering study. The Raman spectra of the InAs/GaAs system show two phonon signal bands related to interface (IF) defects, located at the low-energy side of InAs QDs and GaAs cap layer main phonon peaks, respectively. The int...

We have studied the effects of AlGaAs energy barriers surrounding self-assembled InAs quantum dots in a GaAs matrix on the properties of solar cells made with multiple quantum dot layers in the active region of a photodiode. We have compared the fenced dot samples with conventional InAs/ GaAs quantum dot solar cells and with GaAs reference cells. We have found that, contrary to theoretical pred...

Characterization of electron-beam evaporated Cr-Si0 films (cermet) useful for resistive-gate charge-coupled device (CCD) applications is reported. The films are evaporated from powder sources of different Cr-Si0 compositions. Auger electron spectroscopy (AES) depth profiling is carried out to measure the uniformity of the cermet composition. Electrical conduction in the cermet films is measured...

Heavily Si-doped (5 X 10” cmm3) low-temperature GaAs (LT-GaAs) sandwiched between undoped LT-GaAs layers has been grown by molecular beam epitaxy and annealed to 900 “C. Transmission electron microscopy showed that within the first few minutes of annealing an accumulation of As precipitates formed near each Si-doped/undoped LT-GaAs interface. With further annealing Si segregation to As precipit...

Electron beam methods, such as cathodoluminescence (CL) that is based on an electron-probe microanalyser, and (200) dark field and high angle annular dark field (HAADF) in a scanning transmission electron microscope, are used to study the deterioration of interfaces in InGaP/GaAs system with the GaAs QW on top of InGaP. A CL emission peak different from that of the QW was detected. By using HAA...

We report on various self-assembled In(Ga)As nanostructures by droplet epitaxy on GaAs substrates using molecular beam epitaxy. Depending on the growth condition and index of surfaces, various nanostructures can be fabricated: quantum dots (QDs), ring-like and holed-triangular nanostructures. At near room temperatures, by limiting surface diffusion of adatoms, the size of In droplets suitable f...

In this letter, we have investigated the physical and electrical characteristics of atomic layer deposition of HfO2 on GaAs substrates. X-ray photoelectron spectroscopy XPS analysis revealed no significant reduction of arsenic oxides upon deposition of HfO2 on GaAs using tetrakis dimethyl-amino hafnium Hf NMe2 4 as the metallic precursor. However, XPS confirmed the absence of arsenic oxides at ...

A range of high performance minority carrier devices have been successfully fabricated on Si “virtual” substrates where threading dislocation densities (TDDs) as low as 1x10 cm are routinely achieved. Minority carrier lifetime data achieved on GaAs-on-Si layers exploiting this novel SiGe buffer approach to monolithic integration (τp = 10.5 ns and τn = 1.7ns) verifies the high III-V material qua...

Resonant Tunneling Diodes (RTD) and High Electron Mobility Transistor (HEMT) based on GaAs, as the piezoresistive sensing element, exhibit extremely high sensitivity in the MEMS sensors based on GaAs. To further expand their applications to the fields of MEMS sensors based on Si, we have studied the optimization of the GaAs epitaxy layers on Si wafers. Matching superlattice and strain superlatt...

A model potential for GaAs~100! and InAs~100! surface atoms is developed and surface reconstructions on GaAs~100! and InAs~100! are studied with the conjugate gradient ~CG! method. Not only does this model reproduce well surface energies for the ~100! orientation, it also yields (132) dimer lengths in accordance with ab initio calculations. Large-scale molecular dynamics ~MD! simulations are pe...