Absolute Measurement of the Electron Velocity-Field Characteristic of InSb

Absolute measurements of the electron velocity in InSb at low and high fields have been made, using the combined Shockley---Haynes and time-of-flight technique. Low-field mobilities of 7 ×{} 10⁵ cm/V sec are reported and negative differential mobility is observed at high fields. By comparing the experimental results with numerical solutions of the ambipolar equations, it is demonstrated that the ambipolar errors are of the order of 10-15%. The experimental results are in good agreement with previous low-field measurements and agree over the whole range with the recent Monte Carlo calculations of Fawcett and Ruch.