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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2008. V. 11, N 3. P. 286-291.
Effect of the state of the surface layers on the strength
of materials for optoelectronic and sensors devices
V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine,
41, prospect Nauky, 03028 Kyiv, Ukraine, e-mail: maslov@isp.kiev.ua
Abstract. The goal of this work is to determine the correlation of the strength of brittle
amorphous nonmetallic materials with the defective surface layers and their physical
properties. The defective surface layer of materials for optoelectronic and sensors devices
consists of abundant structural near-surface defects, which are displaced under action of
constant load and thermal fluctuations, reducing the elasticity of the surface layer.
Microcreep processes in tested materials can be described by a general equation that is
known as the logarithmic microcreep equation. The applicability of this equation for
tested optical materials is indicative of the generality of microcreep processes in
crystalline and amorphous hard materials. For each grade of polished optical glass, a
minimal residual defective layer exists. The parameters of this layer are interrelated with
the mechanical properties of glass, such as microhardness and optical strain coefficient,
and thermophysical properties, such as thermal diffusivity, sintering temperature, and
annealing temperature. The greater are the values of these properties, the less is the
concentration of disrupted interatomic bonds. Based on the test results, the corresponding
equation, using the parameter E⋅a 1/2 , for determining the strength of optical silicate glass
and glassceramic has been proposed.
Keywords: microcreep, strength, brittle materials, defective surface layers.
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