Abstract
The stationary Boltzmann equation is solved for electron-hole pairs injected in the semiconductor surface region by means of a monochromatic light field. Profiles of hydrodynamic variables are given as a function of excitation conditions and surface properties. In general, the respective currents result not only from spatial inhomogeneities, but also from ballistic or drift contributions, which can be traced back to the kinetic boundary conditions. Numerical results are given for material parameters typical of indirect semiconductors like Si.