摘要
A theory of multiphoton photoemission is derived to explain the experimentally observed monotonic decrease with the wavelength in the electron yield of TiO_(2) nanoparticles(NPs)by as large as four orders of magnitude.It is found that the fitting parameter corresponds to the energy position of Ti3d e_(g) and t_(2g) states,and the derived theory is a novel diagnostic of excited states in the conduction band,very importantly,applicable to individual NPs.The difference between four-photon slope NPs and three-photon slope NPs is attributed to the difference in defect density.The success of the theory in solving the puzzling result shows that thermal emission from high-lying levels may dominate over direct multiphoton ionization in solids when the photon number larger than four is required.
作者
李博超
李浩
杨畅
季博宇
林景全
富江敏尚
Bochao Li;Hao Li;Chang Yang;Boyu Ji;Jingquan Lin;Toshihisa Tomie(School of Science,Changchun University of Science and Technology,Changchun 130022,China)
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.91850109,11474040,61605017,and 61775021)
the“111”Project of China(Grant No.D17017).