Semiconducting carbon nanotubes(CNTs) possess outstanding electrical and optical properties because of their special one-dimen-sional(1D) structure.CNTs are direct bandgap materials,which makes them ideal for use in optoelectronic devices,e.g.light emitters and light detectors.Excitons determine their light absorption and light emission processes due to the strong Coulomb interactions between electrons and holes in CNTs.In this paper,we review recent progress in CNT photodetectors,photovoltaic devices and light emitters.In particular,we focus on the doping-free CNT optoelectronic devices developed by our group in recent years.
Non-fully oxidized tungsten oxide（WO_（3-x）） nanostructures with controllable morphology were fabricated by adjusting the gas pressure in chemical vapor deposition.The comparative field emission（FE） measurements showed that the obtained W_（18）O_（49） nanowires have excellent FE property.The turn-on field was 7.1 V/μm for 10μA/cm^2 and the observed highest current density was 4.05 mA/cm^2 at a field of 17.2 V/μm.Good electron emission reproducibility was also observed during thermal evaporation and desorption testing.
