Vacuum Ultraviolet Lamp Based Magnetic Field Enhanced Photoelectron Ionization and Single Photon Ionization Source for Online Time-of-Flight Mass Spectrometry

2011 ◽  
Vol 83 (23) ◽  
pp. 8992-8998 ◽  
Author(s):  
Qinghao Wu ◽  
Lei Hua ◽  
Keyong Hou ◽  
Huapeng Cui ◽  
Wendong Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mass Spectrometry ◽  
Vacuum Ultraviolet ◽  
Single Photon ◽  
Time Of Flight ◽  
Ionization Source ◽  
Single Photon Ionization ◽  
Flight Mass Spectrometry ◽  
Photon Ionization ◽  
Ultraviolet Lamp

Single-Photon Ionization, In Situ Optical Diagnostic Of Molecular Beam Epitaxial Growth Of GaAs

1995 ◽  
Vol 406 ◽  
Author(s):  
Adina K. Ott ◽  
Sean M. Casey ◽  
April L. Alstrin ◽  
Stephen R. Leone
Keyword(s):  
Mass Spectrometry ◽  
Real Time ◽  
Molecular Beam ◽  
Single Photon ◽  
Surface Reactions ◽  
Time Of Flight ◽  
Single Photon Ionization ◽  
Flight Mass Spectrometry ◽  
Photon Ionization

AbstractSingle-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) is used in situ to monitor desorbing species and surface reactions during molecular beam epitaxy (MBE) of GaAs. In this method, the 1064 nm fundamental output of a Nd:YAG laser is tripled twice to produce 118 nm (10.5 eV) photons. The pulsed light is passed in front of a growing substrate, giving gaseous scattered molecules sufficient energy to ionize, but not fragment, them. Ionized species are detected with time-of-flight mass spectrometry. Arrangement of the experiment also allows for simultaneous real time monitoring with reflection high-energy electron diffraction (RHEED).Mass spectra are examined and analyzed to quantify fluxes and relative ionization cross sections of growth species. The real time behavior of arsenic and gallium mass signals during epitaxy is presented as a function of substrate temperature and incident gallium flux. Surface reactions are proposed to elucidate mechanisms of arsenic incorporation and compared to measured RHEED results.

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