Monte Carlo simulation of intersubband relaxation in wide, uniformly doped GaAs/AlxGa1-xAs quantum wells

Manfred Dür, Stephen Goodnick, Paolo Lugli

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Using an ensemble Monte Carlo simulation, we have investigated intersubband relaxation of photoexcited electrons in GaAs/AlxGa1-xAs quantum wells having a subband separation smaller than the polar optical phonon energy. Intra- and intersubband scattering through polar optical phonons, acoustic phonons, ionized impurities, and electron-electron scattering are included in the simulation. A comparison is made to recent time-resolved pump and probe experiments performed on uniformly doped samples in which good agreement between theory and experiment is obtained. Our results show that the intersubband decay of electrons from the first excited subband into the ground subband is limited by ionized impurity scattering during the photoexcitation process. Polar optical phonon emission also contributes considerably to the electron decay and occurs from the thermal tail of the heated distribution function in both subbands. Intersubband scattering by intercarrier interaction plays a lesser role for the decay. The heating of the distribution functions is due to ionized impurity intersubband scattering and electron-electron intrasubband scattering, which convert potential energy of an electron into kinetic energy. These mechanisms drive both subbands rapidly towards a single quasiequilibrium distribution with a common electron temperature and chemical potential after the pulse is over. The cooling rate of this distribution function, which governs the intersubband decay, depends initially on the energy relaxation through polar optical phonons, whereas at much longer times acoustic phonon scattering predominates. Thus, the intersubband decay of electrons is nonexponential.

Original languageEnglish (US)
Pages (from-to)17794-17804
Number of pages11
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume54
Issue number24
StatePublished - Dec 15 1996

Fingerprint

Semiconductor quantum wells
quantum wells
Electrons
Phonons
Scattering
electrons
simulation
Distribution functions
decay
scattering
phonons
Electron scattering
distribution functions
Impurities
impurities
electron scattering
Acoustics
Phonon scattering
acoustics
Photoexcitation

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Monte Carlo simulation of intersubband relaxation in wide, uniformly doped GaAs/AlxGa1-xAs quantum wells. / Dür, Manfred; Goodnick, Stephen; Lugli, Paolo.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 54, No. 24, 15.12.1996, p. 17794-17804.

Research output: Contribution to journalArticle

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