Band-structure determination of GaAs from hot-electron luminescence

We show that band-structure information with an accuracy of up to ±1.0 meV for the first tenth of the Brillouin zone can be obtained from hot luminescence emitted by the transient distribution of laser-excited electrons. With this technique, directionally averaged valence bands can be constructed provided the conduction band is accurately known. It does not allow construction of both the valence band and the conduction band without further information. This new technique is similar to nonangular-resolved photoemission but its resolution is more than an order of magnitude higher. We demonstrate our new technique for 2×${10}^{15}$-${\mathrm{cm}}^{\mathrm{-}3}$ p-doped GaAs:Ge. Our interpretation is supported by line-shape calculations. Compared with a recent k⋅p calculation our result puts the light-hole band about 15 meV lower in energy and the heavy-hole band about 7 meV lower. We also obtain information on electronic impurity states associated with higher conduction-band minima. Intra- and intervalley scattering times can be deduced from measuring the intensities of the hot-luminescence spectra.