MedTechLabs seminar: Crystal growth and characterization of CdTe for radiation detectors

by Roman Grill (Charles University, Prague)

Tuesday 27 Aug 2024, 15:00 → 16:00 Europe/Stockholm

FA32 (AlbaNova Main Building)

CdTe-based semiconductors are nowadays the best materials for the preparation of room temperature spectrally sensitive detectors of high energy radiation. They are used in various applications in medicine, security, non-destructive testing, space research, etc. In this talk, I report on the achievements and knowledge that we have gathered during more than 30 years of CdTe research in the Institute of Physics, Charles University. Basic principles of operation of radiation detectors are presented and the required material properties are defined to meet strict criteria set for high-quality detectors. The entire production line is commented, starting with the growth of single crystals followed by after growth annealing, material characterization, detector manufacture and testing. Theoretical concepts describing all processes will be outlined. Throughout the talk, I will emphasize problems unsolved so far that critically limit the production yield and cause the high price of detectors. Particularly, the talk encompasses following topics: CdTe phase diagram, point defect engineering and self-compensation, chemical diffusion, contactless resistivity mapping, bias- and light-induced space charge formation and sensor polarization, transient current technique, and specific contact designs in sensors.

Videoconference: https://kth-se.zoom.us/j/68528679966