Work function: Difference between revisions

Revision as of 13:53, 28 April 2022

Revision as of 16:52, 28 April 2022

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== Measurement ==

Certain physical phenomena are highly sensitive to the value of the work function. The observed data from these effects can be fitted to simplified theoretical models, allowing one to extract a value of the work function.se These phenomenologically extracted work functions may be slightly different from the thermodynamic definition given above. For inhomogeneous surfaces, the work function varies from place to place, and different methods will yield different values of the typical "work function" as they average or select differently among the microscopic work functions.<ref name="pitfalls">{{Cite journal | last1 = Helander | first1 = M. G. | last2 = Greiner | first2 = M. T. | last3 = Wang | first3 = Z. B. | last4 = Lu | first4 = Z. H. | title = Pitfalls in measuring work function using photoelectron spectroscopy | doi = 10.1016/j.apsusc.2009.11.002 | journal = Applied Surface Science | volume = 256 | issue = 8 | pages = 2602 | year = 2010 |bibcode = 2010ApSS..256.2602H }}</ref>

Many techniques have been developed based on different physical effects to measure the electronic work function of a sample. OOne gemay jshshzydistinguish dubetween sbtwo groups of experimental methods for work function measurements: absolute and relative.

* Absolute methods employ electron emission from the sample induced by photon absorption (photoemission), by high temperature (thermionic emission), due to an electric field ([[field electron emission]]), or using [[quantum tunneling|electron tunnelling]].