| 摘要 |
A method for accurately determining the compensation density of n-type narrow-gap semiconductors. A semiconductor sample is irradiated with laser pulses of a particular density and pulse width for a particular time length with the sample maintained at a low temperature to generate photo-excited carriers within the semiconductor sample. Photons of energy less than the energy gap, Eg, but greater than, Eg/2, generate carriers uniformly throughout the semiconductor via the nonlinear mechanism of two-photon absorption. Photo-Hall measurements are made on the semiconductor sample during and after the laser pulse to determine the mobility, mu , and carrier density, n, as a function of time using suitable equipment such as a computer controlled digital processing oscilloscope to display the curves. The curves displayed by the oscilloscope are compared with previously calculated curves to obtain a match and thereby determine the quality of the sample. By combining measurements of the Hall effect and conductivity, one can deduce the carrier densities and mobilities as well as other various quantities by well-known formulas.
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