Studies Of Optical Emission From The Surfaces Of Ni,GaAs And MgOAl₂O₃ Induced By Highly Charged Xe ^q+?4?q?23?ions

Visible light emission from solid surfaces induced by highly charged ions?HCIs?is very important in the interaction between HCIs and substances.To investigate the effect of potential energy of incident ions in visible light emission,a terminal for measuring visible light emitted from solid surfaces induced by HCIs was built at the320 kV platform for multi-discipline research with HCIs in the Institute of Modern Physics.Then the spectra from the interaction of 0.38V_Bohr(the V_Bohrohr is Bohr velocity)Xe ^q+?4?q?23?ions with the surfaces of metallic Ni,semiconductor GaAs and insulator MgOAl₂O₃ were measured in the range of 250-550 nm and under ultra-high vacuum conditions(5.5×10^-9 mbar).This work is of great scientific significance and application value for understanding the interaction mechanism between HCIs and substances and surface element analysis.The spectra from the interaction of Xe ^q+?4?q?20?ions with Ni surface include Ni I and Ni II spectral lines.The photon yields emitted by sputtering Ni atoms increase slowly with the increase of the charge state of the incident ion when q is less than or equal to 15,and increase sharply with the increase of the charge state of the incident ion when q is greater than or equal to 15.The intensity ratio of spectral line emitted by sputtered Ni atoms in different excited states does not change with the increase of the potential energy of the incident ion.Based on the Monte-Carlo method,sputtering has been simulated,and the photon yields emitted by sputtered Ni I atoms in the interaction of Xe ^q+ions and Ni surface have been calculated.The calculation results are consistent with the experimental results.These results show that in the interaction of Xe ^q+ions and Ni surface,the excitation probabilitys of sputtered atoms increase with the potential energy of the incident ions,resulting in that the photon yields of sputtered atoms increase with the potential energy of the incident ions.In the interaction of Xe ^q+?6?q?23?ions with GaAs,the spectra include Ga I and Ga II spectral lines.The photon yields of sputtered Ga atoms in different excited states increase exponentially with the increase of the potential energy of the incident ions.The photon yields of Ga⁺ions in different excited states increases with the potential energy of the incident ions in different trends.For example,the photon yields of Ga⁺4s5d ions increase slowly,while the photon yields of Ga⁺4s4f ions increase sharply.In the interaction of Xe ^q+?6?q?20?ions with MgOAl₂O₃,the spectra include the Al I,Mg I and Mg II spectral lines.The photon yields of Al atoms,Mg atoms and Mg ions do not change with the increase of the potential energy of the incident ion.The intensity ratio of spectral lines emitted by the excited Mg atoms and Mg⁺ion in different excited state does not change with the increase of the incident ion energy,while the intensity ratio of spectral lines of higher excited Al 3s²3d to excited Al 3s²4s atoms increases with the increase of the potential energy of the incident ion.Our research shows that the effect of potential energy of incident ions is different in visible light emission from the surfaces of metal Ni,semiconductor GaAs,insulator MgOAl₂O₃ induced by HCIs,because of the differences of the free electron density,the electron mobility and excitation mechanism of sputtered atoms in the metals,semiconductors and insulators.For the metal Ni and semiconductor GaAs targets,the increase of the potential energy of incident ion leads to the increase of the number of sputtered Ni atom and Ga atom at excited states,while for insulator MgOAl₂O₃ target,the increase of potential energy of incident ion does not change the number of Al atoms and Mg atoms at excited states.The potential energy of the incident ion does not change the electron population of the excited Ni atom and Ga atom formed by electron transfer excitation,and does not change the electron population of the excited Mg atom formed by band breaking excitation,but changes the electron population of the excited Al atom formed by collision excitation.