The electrical properties and distribution of indium in germanium crystals

Wang, Guojian; Mei, Hao; Meng, Xianghua; Mei, Dongming; Yang, Gang

doi:10.1016/j.mssp.2017.11.004

Cited by 4 publications

(2 citation statements)

References 33 publications

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“…We also study the planar detector performance so that we can explore the properties of the HPGe crystals grown at USD and provide feedback to our crystal-growth group for improving techinques for the growth of high-quality crystals. In our group, the HPGe crystals were grown through the Czochralski method using the zone-refined ingots produced at USD from commercial raw materials [64][65][66][67]. The growth process and the characterization method were described in several papers from our group [45,[68][69][70].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of high-purity germanium detectors with amorphous germanium contacts

et al. 2019

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Large, high-purity, germanium (HPGe) detectors are needed for neutrinoless doublebeta decay and dark matter experiments. Currently, large (> 4 inches in diameter) HPGe crystals can be grown at the University of South Dakota (USD). We verify that the quality of the grown crystals is sufficient for use in large detectors by fabricating and characterizing smaller HPGe detectors made from those crystals. We report the results from eight detectors fabricated over six months using crystals grown at USD. Amorphous germanium (a-Ge) contacts are used for blocking both electrons and holes. Two types of geometry were used to fabricate HPGe detectors. As a result, the fabrication process of small planar detectors at USD is discussed in great detail. The impact of the procedure and geometry on the detector performance was analyzed for eight detectors. We characterized the detectors by measuring the leakage current, capacitance, and energy resolution at 662 keV with a Cs-137 source. Four detectors show good performance, which indicates that crystals grown at USD are suitable for making HPGe detectors.

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Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of high-purity germanium detectors with amorphous germanium contacts

et al. 2019

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“…These reasons make the fabrication of Ge detectors from HPGe crystals and exploration of their properties an important part of underground physics. A group at the University of South Dakota (USD) has been working on HPGe crystal growth and detector development in order to improve the performance of Ge detectors for rare-event physics searches [15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the electrical conduction mechanisms in P-type amorphous germanium electrical contacts for germanium detectors in searching for rare-event physics

et al. 2020

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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 $$2.13^{-0.05}_{+0.07}\mathrm{{A}}^\circ $$ 2 . 13 + 0.07 - 0.05 A ∘ to $$5.07^{-0.83}_{+2.58}\mathrm{{A}}^\circ $$ 5 . 07 + 2.58 - 0.83 A ∘ , 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.

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