Electron-phonon interaction studies in an In_0.52Al _0.48As/In_0.53Ga_0.47As/In_0.52Al _0.48As quantum well structure

Joule heating measurements are carried out over a wide range of temperatures on a two-dimensional electron gas fabricated in an In _0.52Al_0.48As/In_0.53Ga_0.47As/In _0.52Al_0.48As heterostructure system that has a 25 nm wide In_0.53Ga_0.47As quantum well region. The energy loss rate is observed to be an indicator of the electron-phonon coupling processes in these systems. The temperature dependence of the energy loss rate is studied from 30 mK to 30 K and points toward a possible dominant unscreened piezoelectric coupling to the acoustic modes over temperatures of 1-30 K, with boundary scattering in the ohmic contacts gaining importance at very low temperatures. The temperature decay of the energy relaxation time exhibits a T^-3 behavior at high temperatures that transitions to a T ^-1 at lower temperatures and tends to saturation at millikelvin levels.