A New Modification of the Semiconducting Compound K3Sb

Abstract

It is possible to prepare a cubic modification of K3Sb in the form of a thin film by the superficial oxidation of an antimony layer prior to the addition of potassium. Annealing of the film thus formed in an excess of potassium at 160°–170°C results in an apparently irreversible transformation to the purple hexagonal form. An analysis of the optical absorption and photoemission data shows that cubic K3Sb is a p-type semiconductor with a bandgap estimated to be 1.4 eV and an electron affinity between 0.6 and 1.3 eV. The cubic nature of brown K3Sb was determined by x-ray and electron diffraction analyses. These studies show that K3Sb has the DO3 structure, typical of cubic alkali antimonides and bismuthides. The data indicate that the material is essentially ordered.