Growth and and gap of the filed tetrahedral semiconductor LiZnN

摘要

LiZnN can be viewed as a zinc blende-like (ZnN)~- lattic partially filled iwth He-like Li~+ interstitials. LiZnN was synthesized by direct reaction between NH_3 and LiZn and LiZn alloy at around 490 deg C for 4.5 h. The grown crystals were polycrystalline with deep red color anjd showed rapid oxidation and hygroscopy. A typical X-ray-powder-diffraction pattern consisted of the LiZnN phase (space group F43m) with the lattic constant a_0=4.902±0.005 A. The band gap of LiZnN evaluated using photoacoustic spectroscopy was 1.98 eV., which is close to the optical band gap (1.91 eV). The bnad gap of LiZnN is smaller than that of the zinc-blende GaN (3.21 eV at room temperature) indicating he relatively high covalency.