The authors report on room-temperature electrical measurements of three-terminal junctions made from a semiconductor heterostructure. The correlation between the junction size of the devices and the voltages needed to be applied in order to observe the electrical characteristics of three-terminal ballistic junctions is studied. The authors show that the ballistic behavior of electron transport can be observed in a three-terminal junction with a junction size of a few micrometers, much larger than the mean free path of electrons in the material. The results are explained in terms of a bias-induced enhancement of the electron mean free path in the system.
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When a large negative bias is applied to a point contact of a three-terminal junction, the velocity of electrons injected from this point contact into the central junction region can be estimated from , where is the electron Fermi energy in the InGaAs quantum well. The bias enhanced electron mean free path at room temperature can then be approximately calculated from the formula . Using the estimated value of , this formula can be cast into .
