Abstract: To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated ²⁴¹Am (5.48 MeV) radioactive sourceat room temperature. The electron mobility lifetime products (µτ)_e of the CdZnTe crystals were predicted by fittingplots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF techniquewas employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electrondrift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing therise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based ona low In concentration doped CdZnTe crystal with (µτ)_e = 2.3 × 10^-3 cm²/V and µ_e = 1000 cm²/(V·s), respectively, exhibits an excellent γ-ray spectral resolution of 6.4% (FWHM = 3.8 keV) for an un-collimated ²⁴¹Am @ 59.54 keV isotope.

Key words: CdZnTe crystals,   particle pulse height spectra,  charge transport performance,  In/Al doping