Electron heating in GaAs due to electron-electron interactions

The interaction between hot electrons, injected into a confined doped GaAs layer, and cold electrons residing in this layer is studied. Utilizing a hot-electron transistor, we found that the output current is larger than the input current, indicating that electron heating is taking place in the layer. Two possible pictures were considered, one assuming single-particle energy and momentum transfer from hot to cold electrons, and the other assuming that thermal equilibrium is reached among the heated cold electrons. By comparing different devices we conclude that the equilibrium picture describes better the heating process, with measured electron temperatures of 10--20 K. Using a power-balance criterion we estimate the energy relaxation time of the hot injected electrons.