Measurements of dipole domains in indium phosphide using a new point-contact probe

Comparisons are made between previously published domain measurements using capacitive and point-contact probes. The design and characterisation of a new point-contact probe and associated differentiator are described along with an analysis of a model of the specimen and probe, showing that the two must be treatd together as one system, and that the resistance of the probe must be matched to the resistivity of the semiconductor. A fundamental limitation of the point-contact probe may be specimen heating at the probe point. Dipole-domain measurements agree with previous capacitive-probe results and lead to a velocity/field characteristics which suggests a 2-level electron-transfer process in the conduction band.