Impact of crystal defects on carrier transport properties in high-purity germanium crystals

High-purity germanium (HPGe) crystals grown by the Czochralski method in a hydrogen atmosphere were analyzed to study the impact of defects on electrical properties. Microwave-detected photoconductivity (MDP) measurements at room temperature (RT) revealed ring-shaped patterns on the wafers, showing radial variations in minority carrier lifetime (40 to 100 μs). At 83 K, the carrier lifetimes were significantly reduced by a factor of three, showing more pronounced ring-shaped patterns. These patterns correlate well with dislocation densities mapped on the wafer using etch pit density (EPD) analysis. Regions with both high dislocation density and dislocation-free zones exhibit reduced lifetimes, indicating the presence of deep-level defects. Temperature-dependent Hall effect (TDH) measurements on p -type samples revealed defects with activation energies of 0.019, 0.065, 0.2, and 0.25 eV. In the n -type sample, a minority carrier trap at 0.34 eV was identified with the deep level transient spectroscopy (DLTS). The mobility in the p -type samples increased with decreasing temperature, showing the highest mobility at 77 K (46,000 cm 2 V −1 ·s −1 ), while the n -type samples showed fluctuating mobility. Combined analysis of MDP, EPD, TDH, and DLTS data highlights the role of both extended and point defects in limiting carrier lifetime and mobility in detector-grade HPGe crystals. • High-purity germanium (HPGe) single crystals were grown by Czochralski Method. • Lifetime mapping at 83 K reveals dislocation-driven recombination in HPGe wafers. • Vacancy-related traps detected by TDH strongly affect the hole trapping behavior. • Spatial inhomogeneity of lifetime correlates with the dislocation distribution. • Combined Hall, TDH, and MPD mapping used to link defects with carrier transport.