EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Infrared detectors based on II-VI semiconductors are cooled from room temperature (RT) to cryogenic temperatures between 80 K and 150 K in order to operate with strong requirements regarding sensor performances for infrared detection. At these cryogenic temperatures, the mechanical properties of II-VI alloys have to be known in details to improve both handling, use and lifetime of infrared sensors. We have developed a cryogenic indentation tool and in-situ measured the mechanical properties of CdZnTe alloys at both room temperature and 90 K. CdZnTe hardness increases by a factor of about 3 when cooling from RT to 90 K, from 0.6 GPa to 1.6 GPa. The plastic flow driving mechanism shows at least two different domains with activation energies around 0.01 eV at low temperatures and around 0.05 eV at RT, showing an increase by a factor of about 2. Radial cracks can be in-situ detected. Toughness of CdZnTe alloys also increases dramatically by a factor of about 2 with cooling down to cryogenic temperature from 0.13 MPa.m1/2 at RT to 0.25 MPa.m1/2 at 90 K.