in this paper, we examine the effect of the energy difference between the l- and the -valleys in compound semiconductor materials, carrier effective mass, and the scattering processes on the electron transport characteristics in mesfets. to do this, we use the monte carlo simulation to demonstrate the superiority of the ingaas mesfet, made on a semi-insulating inp substrate, over both inp and ...

We have investigated the effect of laser irradiation on the terrace morphology of Br-covered GaAs ~110!. Layer-by-layer etching of GaAs ~110! is demonstrated through laser-induced etching and atomic desorption. Nanosecond pulsed-laser irradiation ~hn52.3 eV, pulse power ;35 mJ cm! of Br–GaAs ~110! initially produces a high density of small, single-layer etch pits as Br is consumed. Continued la...

Ultrafast terahertz spectroscopy can be used to probe charge and spin dynamics in semiconductors. We have studied THz emission from bulk InAs and GaAs and from GaAs/AlGaAs quantum wells as a function of magnetic field. Ultrashort pulses of THz radiation were produced at semiconductor surfaces by photoexcitation with a femtosecond TiSapphire laser, and we recorded the THz emission spectrum and t...

This paper describes the development of a heterojunction AlGaAs/GaAs PIN diode as a revolutionary improvement as compared to the homojunction GaAs PIN diode commonly used in microwave systems for commercial and military applications. In a heterojunction device the injected carriers from the junction are confined by the bandgap discontinuity between the AlGaAs/GaAs layers. This confinement effec...

Real-time, in situ observations of surface chemistry during the remote plasma passivation of GaAs is reported herein. Using attenuated total reflection Fourier transform infrared spectroscopy, the relative concentrations of -As-O, -As-H, -H,O, and -CHz bonds are measured as a function of exposure to the effluent from a microwave discharge through NH,, NDs, Hz, and D,. The photoluminescence inte...

A novel use of GaAs, namely, as a scaffold for a heterogeneous palladium catalyst, is proposed. Hydroxy groups on the GaAs surface play important roles. During the adsorption of Pd(OAc)(2) on the GaAs surface, the hydroxy groups attract Pd(ii) species by anion exchange. A subsequent redox reaction proceeds to generate Pd(0) nanoparticles, which are stabilized on the GaAs surface. This process i...

This paper presents a method to implement hazardfree functional blocks for self-timed GaAs MESFET-based circuits. The association of the GaAs technology, offering better electrical performance, higher radiation hardness and wider operating temperature range than Silicon one, with the asynchronous digital design, which avoids the generation and routing of global clock signals and consequently th...

A model that explains the unusual characteristics of the AlGaAs/GaAs modulation-doped field-effect transistor (MODFET) with InAs quantum dots incorporated in the GaAs channel is presented. It is shown that the negative charge of electrons confined in quantum dots decreases the threshold gate–drain voltage at which the channel is fully depleted. This provides an impact ionization of quantum dots...

In order to implement an integrated optical quantum circuit, designing waveguides based on the quantum box is of prime importance. To do this we have investigated optical waveguide both with and without optical pumping. The rate of absorption and emission using an array of AlGaAs/GaAs quantum box core/shell structure in the optical waveguide with various pumping intensities has computed. By con...