Growth and characterisation of wide-bandgap, I-VII optoelectronic materials on silicon

摘要

gamma-CuCl is a wide-bandgap (E-g = 3.395 eV), direct bandgap, semiconductor material with a cubic zincblende lattice structure. Its lattice constant, a(CuCl) = 0.541 nm, means that the lattice mismatch to Si (a(Si) = 0.543 nm) is < 0.5%. gamma-CuCl on Si-the growth of a wide-bandgap, direct bandgap, optoelectronics material on silicon substrates is a novel material system, with compatibility to current Si based electronic/optoelectronics technologies.The authors report on early investigations consisting of the growth of polycrystalline, CuCl thin films with layer thicknesses of 100 nm to 1 mu m on Si (100), Si (111), and quartz substrates by physical vapour deposition. X-ray diffraction (XRD) studies indicate that CuCl grows preferentially in the (111) direction but an epitaxial alignment with the substrate is also detected to a lesser extent in the case of Si (100). Photoluminescence (PL) and Cathodoluminescence (CL) reveal a strong room temperature Z(3) excitonic emission at approximate to 387 nm. X-ray microanalysis and XRD are used to investigate the effect of heat treatments on the CuCl thin films after deposition in the temperature range of 50 to 430 degrees C, (melting point of CuCl approximate to 430 degrees C). It is a found that a reaction occurs with Si on heating above 250 degrees C forming SiCl4 and Cu. (C) 2005 Springer Science + Business Media, Inc.