Thermal effects and kinetics in step-flow crystal growth of α-HgI 2

Abstract

In the present paper a step-flow problem accounting for adsorption and sublimation heat releases coupled with conductive heat transfer into the substrate is considered for the {110} vicinal face of α-HgI 2 crystal vapor growth. The crystal growth of α-HgI 2 on the {110} face proceeds under the combined control of (i) a high coverage factor (∼ 0.75−0.95), (ii) surface diffusion, (iii) thermally activated incorporation kinetics and (iv) thermal effects of adsorption and incorporation heats released in the vicinity of the steps coupled with conductive heat transfer through the growing crystal. It is shown that the sequence of steps moving across the crystal face produces a sequence of temperature waves with the amplitudes of 0.04 to 0.06 K. When the crystal thickness is small enough (less than ∼ 300 μm), the temperature fields of neighboring steps do not interfere, thus the steps are thermally isolated. However, when the crystal thickness is sufficiently large, the temperature field on the terraces becomes the superposition of thermal effects resulting from the whole sequence of steps.