The Impact of the Charge Barrier Height on Germanium (Ge) Detectors with Amorphous-Ge Contacts for Light Dark Matter Searches

Abstract

Germanium (Ge) detectors with ability of measuring a single electron-hole (e-h) pair are needed in searching for light dark matter (LDM) down to the MeV scale. We investigate the feasibility of Ge detectors with amorphous-Ge (a-Ge) contacts to achieve the sensitivity of measuring a single e-h pair, which requires extremely low leakage current. Three Ge detectors with a-Ge contacts are used to study the charge barrier height for blocking electrons and holes. Using the measured bulk leakage current and the D$\ddot{o}$hler-Brodsky model, we obtain the values for charge barrier height and the density of localized energy states near the Fermi energy level for the top and bottom contacts, respectively. We predict that the bulk leakage current is extremely small and can be neglected at helium temperature ($\sim$4 K). Thus, Ge detectors with a-Ge contacts possess the potential to measure a single e-h pair for detecting LDM particles.

arXiv comment10 pages, 13 figures

References in corpus (15)

• New results from DAMA/LIBRA
• Results from 730 kg days of the CRESST-II Dark Matter Search
• Direct Detection of Sub-GeV Dark Matter
• First dark matter search results from a 4-kg CF${}_3$I bubble chamber operated in a deep underground site
• Results on MeV-scale dark matter from a gram-scale cryogenic calorimeter operated above ground
• Direct Search for Low Mass Dark Matter Particles with CCDs
• First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB
• First dark matter search results from the PandaX-I experiment
• Distillation of Liquid Xenon to Remove Krypton
• Equivalent Neutrinos, Light WIMPs, and the Chimera of Dark Radiation
• Limits on MeV Dark Matter from the Effective Number of Neutrinos
• Directional Sensitivity In Light-Mass Dark Matter Searches With Single-Electron Resolution Ionization Detectors
• Ultra-Low Noise Mechanically Cooled Germanium Detector
• Direct Detection of MeV-Scale Dark Matter Utilizing Germanium Internal Amplification for the Charge Created by the Ionization of Impurities
• Fabrication and Characterization of High-Purity Germanium Detectors with Amorphous Germanium Contacts

Cited by in corpus (3)

• Characterization of High-Purity Germanium Detectors with Amorphous Germanium Contacts in Cryogenic Liquids
• Evidence of cluster dipole states in germanium detectors operating at temperatures below 10 K
• Development of Planar P-type Point Contact Germanium Detectors for Low-Mass Dark Matter Searches