Two-dimensional Hot Electrons Research Articles

Two-dimensional hot-electron models for short-gate-length GaAs MESFET's

A detailed hot-electron device model suitable for modeling short-gate-length GaAs MESFET's is described. A two-dimensional numerical simulation is used to solve a set of semiclassical carrier transport equations, including a full rigorous solution of the energy conservation equation. The importance of the hot-electron effects is demonstrated and in particular the role of the electron temperature gradient in addition to velocity overshoot is emphasized. The influence of doping and mobility profiles are investigated and found to have a very significant effect on the device characteristics. The model is applied to a range of submicrometer-gate-length devices and is shown to be useful for characterizing devices with gate lengths down to less than 0.1 µm. The dependence of saturated drain current on gate length is quantified.

Nonequilibrium phonon effect on time-dependent relaxation of hot electrons in semiconductor heterojunctions.

We have studied the effect of a nonequilibrium population of optical phonons on the energy relaxation of two-dimensional (2D) hot electrons in a semiconductor quantum well. A time-dependent analysis of the coupled electron--LO-phonon system is presented. The 2D electrons are described by a temperature ${T}_{e}$(t). The dynamics of the nonequilibrium lattice excitations is governed by a kinetic equation for ``phonon wave packets'' that was derived recently by us. If the lifetime of the LO phonons is larger than 5 psec, phonon reabsorption can slow down considerably the carrier cooling. The time evolution of the carrier temperature is calculated. The comparison with recent experiments is discussed.

Screened electron-polar optic phonon interaction and power loss of hot electrons in bulk GaAs and in quantum wells

The power loss of hot two-dimensional electrons in MQWs calculated by taking the proper matrix element due to the bulk nature of the phonons and the screening agrees well with the experimental data for 2 K. It is also found that the electron temperature is higher in MQWs than in bulk for the same power input.

Two-dimensional electron transport and hot electron effects in InP/n-AlInAs heterostructures

Abstract We report two-dimensional electron gas (2DEG) transport in InP/n-AlInAs Heterostructures. This is the first demonstration of forming 2DEG in an InP with semiconductor heterojunctions. Temperature and electron density dependences of the 2DEG mobility are presented. This 2DEG system can be utilized for high speed and high power FETs. Hot electron gas transport in an InP is simulated with including electron-electron scattering and screening by high density electrons.

Electron heating and free-carrier absorption in GaAs/AlGaAs single heterostructures

We observe far infrared broadband emission from the hot two-dimensional electron plasma in GaAs/AlGaAs single heterostructures grown by molecular beam epitaxy. The radiation is analyzed in two different frequency regimes (around 35 and 100 cm−1). From the relative dependence of the intensities on the applied longitudinal electric field the hot-electron temperatures are determined. From the absolute emission intensities values of the free-carrier absorption coefficient (down to 10−5 in ultrahigh mobility samples) are measured.

Monte Carlo simulation of two-dimensional hot electrons in n-type Si inversion layers

Monte Carlo simulation is carried out to study high field transport of the two-dimensional electron gas formed on the (100) surface of silicon. Good agreement is obtained between the measured and calculated results. The saturation of the drift velocity is found to depend on the magnitude of the first-order intervalley phonon scattering.

Two-dimensional hot-electron transport in quantum-well structures of polar semiconductors

The drift velocity of hot electrons itinerant two dimensionally in a semiconductor quantum-well structure is calculated at different lattice temperatures on a displaced Maxwellian model. Interactions with deformation potential acoustic and polar optic phonons are considered using the analytic expressions obtained on the basis of a momentum conservation approximation. Contrary to a previous prediction, no negative differential resistance is obtained.