The zinc sulfide electroluminescence(EL) thin film doped with erbium,fabricated by thermal evaporation with two boats,are made and analyzed by the technology of X-ray photoelectron spectroscopy.The information of surf...The zinc sulfide electroluminescence(EL) thin film doped with erbium,fabricated by thermal evaporation with two boats,are made and analyzed by the technology of X-ray photoelectron spectroscopy.The information of surface states of the microcrystalline thin films is obtained.The transient EL spectroscopy of the thin film devices is measured and simulated by the formulae of different energy transfer mechanism.The results indicate that the formula of Gaussian line shape can fit well for description of transient EL process of zinc sulfide thin film doped with erbium.It shows that the surface states have important effect on the relaxation peaks during the decay process of EL for the thin film devices.展开更多
We report substantial improvements and modulation in the photocurrent （PC） and photoluminescence （PL） spectra of monolayer MoS2 recorded under electrostatic and ionic liquid gating conditions. The photocurrent and...We report substantial improvements and modulation in the photocurrent （PC） and photoluminescence （PL） spectra of monolayer MoS2 recorded under electrostatic and ionic liquid gating conditions. The photocurrent and photo- luminescence spectra show good agreement with a dominant peak at 1.85 eV. The magnitude of the photoluminescence can be increased 300% by ionic liquid gating due to the passivation of surface states and trapped charges that act as recombination centers. The photocurrent also doubles when passivated by the ionic liquid. Interestingly, a significant shift of the PL peak position is observed under electrostatic （14 meV） and ionic liquid （30 meV） gating, as a result of passivation. The ionic liquid provides significant screening without any externally applied voltage, indicating that these surface recombination centers have net charge. The acute sensitivity of monolayer MoS2 to ionic liquid gating and passivation arises because of its high surface-to-volume ratio, which makes it especially sensitive to trapped charge and surface states. These results reveal that, in order for efficient optoelectronic devices to be made from monolayer MoS2, some passivation strategy must be employed to mitigate the issues associated with surface recombination.展开更多
文摘The zinc sulfide electroluminescence(EL) thin film doped with erbium,fabricated by thermal evaporation with two boats,are made and analyzed by the technology of X-ray photoelectron spectroscopy.The information of surface states of the microcrystalline thin films is obtained.The transient EL spectroscopy of the thin film devices is measured and simulated by the formulae of different energy transfer mechanism.The results indicate that the formula of Gaussian line shape can fit well for description of transient EL process of zinc sulfide thin film doped with erbium.It shows that the surface states have important effect on the relaxation peaks during the decay process of EL for the thin film devices.
文摘We report substantial improvements and modulation in the photocurrent （PC） and photoluminescence （PL） spectra of monolayer MoS2 recorded under electrostatic and ionic liquid gating conditions. The photocurrent and photo- luminescence spectra show good agreement with a dominant peak at 1.85 eV. The magnitude of the photoluminescence can be increased 300% by ionic liquid gating due to the passivation of surface states and trapped charges that act as recombination centers. The photocurrent also doubles when passivated by the ionic liquid. Interestingly, a significant shift of the PL peak position is observed under electrostatic （14 meV） and ionic liquid （30 meV） gating, as a result of passivation. The ionic liquid provides significant screening without any externally applied voltage, indicating that these surface recombination centers have net charge. The acute sensitivity of monolayer MoS2 to ionic liquid gating and passivation arises because of its high surface-to-volume ratio, which makes it especially sensitive to trapped charge and surface states. These results reveal that, in order for efficient optoelectronic devices to be made from monolayer MoS2, some passivation strategy must be employed to mitigate the issues associated with surface recombination.
