https://doi.org/10.1140/epjc/s10052-020-08529-z
Special Article – Tools for Experiment and Theory
Investigation of the electrical conduction mechanisms in P-type amorphous germanium electrical contacts for germanium detectors in searching for rare-event physics
Department of Physics, University of South Dakota, 414 E Clark St, 57069, Vermillion, SD, USA
Received:
24
March
2020
Accepted:
7
October
2020
Published online:
15
October
2020
For the first time, electrical conduction mechanisms in the disordered material system is experimentally studied for p-type amorphous germanium (a-Ge) used for high-purity Ge detector contacts. The localization length and the hopping parameters in a-Ge are determined using the surface leakage current measured from three high-purity planar Ge detectors. The temperature dependent hopping distance and hopping energy are obtained for a-Ge fabricated as the electrical contact materials for high-purity Ge planar detectors. As a result, we find that the hopping energy in a-Ge increases as temperature increases while the hopping distance in a-Ge decreases as temperature increases. The localization length of a-Ge is on the order of 
to 
, depending on the density of states near the Fermi energy level within bandgap. Using these parameters, we predict that the surface leakage current from a Ge detector with a-Ge contacts can be much smaller than one yocto amp (yA) at helium temperature, suitable for rare-event physics searches.
This work was supported in part by NSF NSF OISE 1743790, NSF PHYS 1902577, NSF OIA 1738695, DOE Grant DE-FG02-10ER46709, DE-SC0004768, the Office of Research at the University of South Dakota and a research center supported by the State of South Dakota.
© The Author(s) 2020
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Funded by SCOAP.3
