Comparison of Lateral Crystal Growth in Selenium Thin Films and Surface of Bulk Samples

Abstract

Crystal growth in the surface of selenium bulk samples and in selenium thin films of different thicknesses has been studied under isothermal conditions using different microscopy techniques (optical, infrared, and scanning electron microscopy). The structure of the formed crystals is described with respect to previous publications focused on crystal growth in selenium thin films and bulk samples. Crystal growth rates were obtained from the linear dependence of crystal sizes on annealing time. Such behavior assumes that crystal growth is driven by liquid–crystal interface kinetics. The crystal growth rates found in the surface of bulk samples are comparable with those found in thin films and a few orders of magnitude higher than previously published growth rates of volume crystals formed in selenium undercooled melts. The crystal growth rates were scaled with the viscosities to analyze the Stokes–Einstein relation. A relatively high decoupling between the crystal growth rate and viscosity occurs in the studied samples of amorphous selenium. Therefore, the standard screw dislocation growth model is corrected for the decoupling, which provides a satisfactory description of the crystal growth rate over a wide temperature range.

Analysis of crystal growth and viscosity in Ge-Sb-Se-Te undercooled melts

“…The standard growth models are based on an assumption, that the own transport of the structural units to the liquid-crystal interface is driven by self-diffusion, which can be substituted by inverse viscosity according to the Stokes-Einstein-Eyring relation [49]. Nevertheless, in recent studies on crystal growth [13,37,38,48,[50][51][52][53][54] a significant decoupling of crystal growth rate and viscosity occurred, therefore, the standard crystal growth models were corrected to the decoupling phenomenon by including the decoupling parameter  into the standard crystal growth models (Eq. 5).…”

“…Viscosity is very important physical property of the glassy materials not only for fabrication and processing of the glassy materials, but also viscous flow influences kinetic processes taking place in the amorphous materials, such as structural relaxation [9,10] and crystallization [11][12][13][14]. During the crystallization, transport of the structural units to the crystal-liquid interface is driven by diffusivity (Df) which can be substituted by viscosity () via the well-known Stokes-Einstein relation (Df ≈  -1 ).…”

Synergetics of the instability and randomness in formation of gradient modified semiconductor structures

“…The stationary solutions of the equation (4) in the homogeneous case (G = g source ) are determined by the correlations:…”

“…Amorphous chalcogenides (S, Se, Te) and their multicomponent alloys are very interesting objects with wide practical applications. Due to the transparency in the near, medium and far infrared regions, their significant non-linearity, chalcogenide semiconductor materials are used as active and passive elements in optics and sensor devices [3,4], telecommunications [1] as a thermal image and generation of nonlinear light [3][4][5]. Intensive and reverse crystallization observed in some thin-film systems of chalcogenides is the basis for using these materials in creation of non-volatile memory [3,[5][6].…”

“…Intensive and reverse crystallization observed in some thin-film systems of chalcogenides is the basis for using these materials in creation of non-volatile memory [3,[5][6]. The mentioned applications of the chalcogenide materials of As(Ge)-S(Se, Te) systems could not be realized without the knowledge of the basic properties and processes occurring in these unique materials [4,[6][7][8][9][10]. In addition, the fundamental research into the influence of random processes on formation of the structure of modified semiconductor systems by using synergetics and computer simulation is extremely important [11][12][13].…”