Investigation of Amorphous Germanium Contact Properties with Planar Detectors Made from Home-Grown Germanium Crystals

TL;DR

This study fabricates and characterizes planar germanium detectors made from high-purity crystals grown at USD, focusing on amorphous Ge contacts and their electrical and spectroscopic performance.

Contribution

It introduces a fabrication method for planar detectors with amorphous Ge contacts from USD-grown crystals and evaluates their electrical and spectroscopic properties.

Findings

Good quality of USD-grown crystals confirmed

Electrical contacts exhibit desirable properties

Detectors demonstrate effective spectroscopy performance

Abstract

The characterization of detectors fabricated from home-grown crystals is the most direct way to study crystal properties. We fabricated planar detectors from high-purity germanium (HPGe) crystals grown at the University of South Dakota (USD). In the fabrication process, a HPGe crystal slice cut from a USD-grown crystal was coated with a high resistivity thin film of amorphous Ge (a-Ge) followed by depositing a thin layer of aluminum on top of the a-Ge film to define the physical area of the contacts. We investigated the detector performance including the $I$-$V$ characteristics, $C$-$V$ characteristics and spectroscopy measurements for a few detectors. The results document the good quality of the USD-grown crystals and electrical contacts.