Hot-electron energy relaxation in GaAs/GaAlAs two-dimensional structures: importance of two-phonon processes

Abstract

The energy relaxation of hot electrons has been studied in GaAs/GaAlAs two-dimensional structures with emphasis on the role of two-phonon processes for the first time. An expression for the power loss due to electron-two-zone edge transverse acoustic (TA) phonon interaction is derived using the effective carrier-two-phonon interaction Hamiltonian. Numerical calculations for the power loss are presented over a wide electron temperature range by incorporating the electron-two-zone edge TA phonon interaction besides the usual one-phonon scattering. The hot phonon effect for the polar optical phonon scattering has also been included. The very good agreement between the calculations and the experimental data in the GaAs/GaAlAs systems demonstrates the importance of electron-two-phonon scattering processes in power loss from hot electrons.

Hot Electron Transport in Two-dimensional SiGe/Si Quantum Wells

“…In the temperature region we considered here indicates that acoustic deformation potential scattering mechanism is dominant mechanism compared to piezoelectric scattering mechanism. The same dominant mechanism was also observed in 2D GaAs, GaN, GaInAs quantum wells [17][18][19]. In the acoustic deformation potential scattering mechanism, the only adjustable parameter is the deformation potential constant E d .…”

“…Here only the first subband is assumed to be occupied. It is convenient to calculate average energy loss per electron by calculating the energy gained by phonons from the electrons and dividing by the number of electrons ( ) participate [17]…”

“…In both the scattering mechanisms, we incorporated dynamical screening effect. The inclusion of dynamical screening effect reduces the energy loss rate an order of magnitude [17,18]. Figure 2 shows the variation of energy loss rate with quantum well width in the acoustic deformation potential scattering with a deformation potential constant E d = 12.0 eV, at T e =10.0K and carrier concentration N s =1.0x10 13 m -2 .…”

Electron cooling in three-dimensional Dirac fermion systems at low temperature: Effect of screening

“…Hot electron relaxation, at low temperature, depends purely on electron-acoustic phonon interaction and is used as tool to determine the electron-phonon coupling strength. Hot electron cooling is extensively studied in bulk semiconductors [12][13], conventional two-dimensional electron gas (2DEG) of lowdimensional semiconductor heterostructures [14][15][16][17][18][19][20][21], graphene [22][23][24][25][26][27][28][29][30][31][32][33][34][35] and monolayer MoS 2 [36]. In bulk semiconductors electron gas is three-dimensional (3DEG) and in the latter three systems electron gas is 2DEG.…”