Polygermyne - a prototype system for layered germanium polymers

Abstract

The topochemical reaction of CaGe2 with HCl was studied at low temperature. The resulting product is the new crystalline layered compound polygermyne (GeH)n, which is isomorphic to polysilyne (SiH)n. The layers are stacked in a six-fold sequence with a separation of 5.65 angstroms. Polygermyne exhibits a very intense near infrared photoluminescence. This property, together with the possibility of epitaxial preparation on Ge substrates, suggests future optoelectronic applications, which are of interest since Ge itself cannot luminesce strongly due to its indirect bandgap.