UBC Theses and Dissertations
Microwave cyclotron resonance of hot electrons in p-type gallium antimonide Hill, Douglas Arthur
A microwave photocreated cyclotron resonance signal is observed in p-type GaSb in the temperature range 1-30 K. Circular polarization and other measurements identify the carriers as electrons in the (000) conduction band. The effects of background absorption, dispersion, the presence of holes at high power and plasma shifts are taken into account. The problem of a surface effect on the measured peak position is reported for the first time, and is avoided by bulk carrier creation. The electrons are heated by the strong microwave electric field to energies up to 30 ± 4 meV above the conduction band minimum. The scattering mechanism is studied through the half width of the cyclotron resonance line. The measured ωτ of 1.5 - 4 yields an electron collision time of τ ≈ 10⁻¹¹ s. The scattering mechanism at liquid helium temperatures is identified as being partly due to neutral defect acceptor scattering of hot electrons. There is also an unidentified residual scattering process. The electron polaron effective mass is measured to be m*(polaron)/m[sub o] = 0.0412 ± .0008 for electrons with an average energy of 15 meV. The angular dependence of the effective mass is less than 1%. When corrections for conduction-band non-parabolicity and polaron effects are applied, the band-edge free electron mass is calculated to be msub o]*(free)/m[sub o] = 0.0396 ± 0.0018 (or ± 4.4%). The main error in the final value derives from the two corrections calculated using the hot electron distribution.
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