DFT Theoretical Investigation of Ionization Potential and Electron Affinity of 2,6-Dithiopurine
All the molecular structures of thirty-three possible 2,6-dithiopurine tautomers have been optimized by density functional theory(DFT) method at B3LYP/6-311G(d,p) level.The paper also calculates the HOMO and the LUMO energy,the first ionization potential,electron affinity and energy level gap between HOMO and LUMO on all the tautomers,and Fermi levels in gas phase and aqueous phase.In addition,the paper analyzes and discusses the chemical activity of various isomers in the aqueous phase and gas phase,which will explore useful reference information for this molecular pharmacology activity and experimental study.
Abstract We report on n -channel tunneling field-effect transistors (TFET) with a tensile strained Si channel and a compressively strained Si 0.5 Ge 0.5 source. The device shows good performance with an average subthreshold swing S of 80 mV/dec over a drain current range of more than 3 orders of magnitude. We observed that the on-current increases exponentially with the back gate voltage. At a back gate voltage of 8 V, the on-current was enhanced by a factor of 1.6. The back gate also improves the on/off current ratio. Low temperature measurements show a slightly temperature dependent S , characteristic for a tunneling dominated device.