Adaptive photo-EMF detectors based on CdTe and their solid solutions
The complex measurements of V(Ti)-doped CdTe (crystals and films) and their solid solutions were carried out. This allowed to establish the nature and energy structure of the intrinsic defects and impurity centers and to propose the micromechsnism of photo-EMF effect. The adaptive photodetectors based on these crystals and CdTe polycrystalline films were developed.
CdTe:Ti crystals: materials for optical sensors in the near-IR region
The Ti-doped CdTe semiinsulating crystals of high optical quality were grown by the vertical Bridgman technique. The complex optical, photoelectric and photorefractive measurements of CdTe doped with Ti atoms were carried out. It allowed to our knowledge for the first time to determine the photorefractive characteristics of these crystals. Studies of the optical absorption and photodiffusion current made it possible to determine the nature and energy structure of impurity and intrinsic defects as well as to establish their role in the photorefractive effect. It was shown that the excited 3T1(P) state is in resonance with the conduction band. As a result of it the auto-ionization of electrons to the conduction band under the laser excitation take place. The energy-level diagram both of impurity and intrinsic defects in the CdTe:Ti crystals was constructed. It was shown that titanium dopant have advantage over other dopants and that CdTe:Ti has better characteristics for a potential applications. Obtained parameters: high optical holographic gain coefficient (up to 0.60 cm-1), low background absorption (about 0.1 - 0.2 cm-1), high optical quality and homogeneity, almost electronic type photoconductivity (electron-hole competition factor equals 0.94) show that this material can be effectively used as sensor components for both optical and photoelectric applications in the near infrared region.
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.