Transport of majority and minority carriers in 2-µm-diameter Pt-GaAs schottky barriers

An experimental study of small area (2-µm-diameter) Pt-GaAs Schottky barrier diodes has been made, by using a wafer chip with a matrix of these diodes lying within approximately a minority carrier diffusion length of one another. Using one diode as collector and another as emitter, transistor measurements indicated that the dominant contribution to the current is the majority-carrier thermiconic field emission current for large forward-bias voltage (
V_{EB} \gsim 0.4
V), whereas the smaller forward-bias (
V_{EB} \lsim 0.4
V) recombination in the space-charge region was most important. The minority carrier injection ratio is measurable only for large forward-bias voltages, decreasing from ≃ 10
^-2
to 10
^-5
as V
EB
increases from 0.5 to 1.0 V. The minority carrier diffusion length was measured to be
L_{p} \sime 1.3
µm. These results are of considerable significance for the understanding and optimization of the performance of these devices as classical detectors and mixers.