Hole Mobility in Ge:Ga Far-Infrared Photoconductive Semiconductors at Low Temperatures

概要

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We have examined drift mobility of holes in Ge:Ga semiconductor crystals with low compensation at low temperature (2–4 K) through the measurement of magnetoresistance. The hole mobility of Ge:Ga with Ga concentration of 2×1014 cm-3 is 5.1–6.6×105 cm2 V-1s-1 at bias field of 1.2 V/cm at 2–4.2 K and that with Ga concentration of 1×1014 cm-3 is larger by a factor of 1.5. The dependence of the hole mobility on temperature is small. These experimental results clearly show that the mobility of holes is mainly determined by neutral-impurity scattering. The dependence of the hole mobility on bias electric field is also small. Ge:Ga crystal uniaxially stressed at about 6×103 kg/cm2 shows larger hole mobility by a factor of 1.5 than the unstressed Ge:Ga when they are compared at nearly zero bias field at 2 K, but they have almost the same value when compared at the bias field of a half of each breakdown field. The hole lifetime of the stressed Ge:Ga, which is derived from the photoconductive gain using the measured hole mobility, is 60 times longer than that of the unstressed Ge:Ga.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
1996-09-15