Formation of three-dimensional lead telluride nanoislands on strained barium fluoride (111) surface

摘要

The nucleation and growth of three-dimensional lead telluride (PbTe) nanoislands from vapor phase on BaF2(111) substrates strained by an external load under conditions close to thermodynamic equilibrium have been studied. Evolution of the shape of nanoislands was traced and their size distribution was statistically analyzed as dependent on the character of straining of the substrate. Homogeneous arrays of faceted PbTe nanoislands with an ultrahigh surface number density (above 10(11) cm(-2)) and an average height of h(1) similar to 3.5 nm (at a 8-9% rms deviation) are obtained for the first time on elastoplastically strained BaF2(111) substrates under the conditions of small vapor supersaturation in the condensation zone. The formation of nanoisland arrays with such parameters is possible due to (i) the heterogeneous nucleation of PbTe nanoislands at the surface monatomic slip steps aligned in the < 110 > direction and (ii) the influence of straining on the kinetic processes on the substrate surface.