Fig. 2: Vapor pressures and structures of metal–organic precursors.
From: Hybrid molecular beam epitaxy of germanium-based oxides
a Vapor pressures of common elements in Ge-based oxides compared to precursors for hybrid MBE. b–g The chemical structures of the precursors including hexamethylditin (HMDT, b)16,38, hexamethyldigermanium (HMDG, c), titanium tetraisopropoxide (TTIP, d)39,40, germanium tetraisopropoxide (GTIP, e), vanadium oxytriisopropoxide (VTIP, f)41, and zirconium tert-butoxide (ZTB, g)42,43. All metal vapor pressures use the equations from Alcock and coworkers44. Ge uses a fit to data from ref. 45. The vapor pressures for GTIP, TTIP, and VTIP use Antoine parameters from ref. 46 who themselves took this data from ref. 47. HMDT data use the enthalpy of vaporization from ref. 48 and the standard entropy of vaporization fit to boiling temperatures from chemical suppliers. HMDG data use Trouton’s rule along with a boiling temperature provided from Sigma-Aldrich.
