Ab initio and Monte Carlo studies of physical properties of semiconductor radiation detectors

The structural and electronic properties of Cd 1− x Zn x Te and Cd 1– x Mn x Te compound semiconductors are investigated by using the first-principles pseudopotential plane-wave method based on the density functional theory (DFT). The generalized gradient approximation (GGA) and the local density approximation (LDA) are used. The calculated lattice parameters, the bulk modulus and the electronic band structures of different alloys are found to be in good agreement with the literature data. Absolute, photopeak and intrinsic detection efficiencies, in the 511–1332.5 keV gamma-ray energy range, are investigated using a stochastic approach, which is the Monte Carlo method as implemented in the Geant4 code. The calculated parameters are analyzed in the light of the available data.