Electron-hole drag in semiconductors

摘要: Abstract Transport of minority carriers in semiconductor plasmas can be strongly affected by electron-hole scattering. In high-mobility carrier systems not only the presence one type, but also its drift velocity determines transport other type via This effect is known as “carrier drag”. modulation-doped quantum well structures drag strong enough to cause “negative absolute mobility” both electrons and holes. this paper we describe all-optical measurements, from which momentum relaxation times scattering are quantitatively determined. Extremely short result for a hole plasma (40 100 fs) contrast reverse case holes an electron (2–5 ps). The physical reasons (mass ratio, degeneracy, two-dimensionality) discussed, new phenomena negative photoconductivity instabilities drag.