Olga V. Voevodina

Doped GaSe nonlinear crystals

The physical properties of pure GaSe and the crystals doped with 0.01÷3% Al, In, Te, and S have been observed comparatively to reveal the potentials for frequency conversion of laser emission. It has been shown that GaSe:S(greater than or equal to 3%) is the most promising material for practical applications.

ZnGeP2 crystal is the leader among nonlinear crystals for middle IR

The results of 25-year work on design of middle IR ZnGeP2 crystal growing technology are summed up, so as of the 20-year work on investigation of the parametric frequency converters with this crystal.

Properties of gallium selenide doped with sulfur from melt and from gas phase

This paper presents the results of investigation on influence of doping with sulfur and annealing in sulfur atmosphere on properties of promising nonlinear optical gallium selenide crystals, grown by the Bridgeman method from melts with content of sulfur 0.01-3 mass % and annealed in sulfur atmosphere.

Annealing of Some II-IV-V2 Crystals in the Vapor of Volatile Constituents

Abstract : Experiments on annealing of CdGeAs2-, CdSnAs2- and ZnGeP2-crystals in the vapor of volatile constituents were carried out. Conductivity and Hall effect measurements were performed to characterize the modification of electrical properties, caused by the interaction of the crystal with the gas phase during annealing. Literature data and the results of the present work are discussed based on the results of a quasi-chemical analysis. This yielded that the results of annealing depends essentially on both the conditions of the experiment and the initial imperfection of the crystal. The most probable native structural defects becoming apparent under the annealing were the following: for CdSnAs2 - Sn(sub Cd), V(sub As); for CdGeAs2 - V(sub As, V(sub cd), Cd(sub Ge), Ge(sub Cd); for CdSiAs2 - Si(sub As), V(sub As); for CdSiP2 - V(sub Cd), V(sub p); for ZnGeP2 - Zn(sub Ge), Ge(sub Zn), V(sub Zn), V(sub p); and for ZnSnP2 - Zn(sub Sn), Sn(sub Zn), V(sub Zn), V(sub p).

II-IV-V2 and I-III-VI2 nonlinear optical crystals for mid-IR-range : Schottky defects concentration

The work deals with ternary nonlinear optical crystals of I- III-VI2, and II-IV-V2-type. Theoretical thermodynamic method of quasi-chemical reactions was used. Entropy of vacancy was calculated as sum of configuration and vibration components. For the first one uncertainty in positions of new bonds formed by unpaired electrons arisen when one of consistent atoms is deleted and uncertainty in new positions of relaxing atoms were considered. Standard Boltzmann expression for configuration entropy (Delta) Sconf equals (Sigma) klnw and geometry considerations were used. It was assumed that the vibration component is caused by change in vibration frequency of atoms surrounding formed vacancy. Change in length of bonds and in bonding force took into account. Approximate expression for vibration entropy change (Delta) Svibr equals 3Nkln, geometry considerations and results of bonds lengths calculations were used.

Thermodynamics of self-propagating high-temperature synthesis of ternary semiconductors

Fourteen A2B4C25- and A1B3C26-compounds with chalcopyrite-type crystal structure are under investigation. The process of formation of a sole ternary compound form chemical elements is dealt with. Design-based model anticipates adiabatic conditions. Characteristics of the self-propagating high-temperature synthesis such as adiabatic combustion temperature, initial temperature of synthesis process, share of liquid phase in combustion product are calculated.

Doping of ternary compounds CdGeAs2 and CdSnAs2 by impurities of I, II and III groups

Abstract Research in doping processes of ternary chalcopyrites A 2 B 4 C 2 5 is of primary interest for several reasons. First of all, a study of the dependencies of ‘the properties of crystal vs. the concentration of impurity in melt’ decides a fundamental problem. It is a check on the theory of ordering of a crystal structure for some specifically defined values of dopant concentration leading to a possible phase transformation caused by the self-organization of large-scale fluctuations in a melt. On the other hand, it is necessary also for practical tasks—for example, obtaining high-resistance CdGeAs 2 -crystals for use in nonlinear optics. In the present work data on electrical activity and on an effect in the electrophysical properties of ternary semiconductors CdGeAs 2 and CdSnAs 2 are obtained for dopants of Au, Cu, Zn, In, Sc and Gd in CdGeAs 2 and for Au, Cu and In in CdSnAs 2 , added to a melt during synthesis or recrystallization of a material.