Dember effect

In physics, the Dember effect is when the electron current from a cathode ( I 3 ) {displaystyle (I_{3})} subjected to both illumination and a simultaneous electron bombardment is greater than the sum of the photoelectric current ( I 1 ) {displaystyle (I_{1})} and the secondary emission current ( I 2 ) {displaystyle (I_{2})} . In physics, the Dember effect is when the electron current from a cathode ( I 3 ) {displaystyle (I_{3})} subjected to both illumination and a simultaneous electron bombardment is greater than the sum of the photoelectric current ( I 1 ) {displaystyle (I_{1})} and the secondary emission current ( I 2 ) {displaystyle (I_{2})} . Discovered by Harry Dember (1882–1943) in 1925, this effect is due to the sum of the excitations of an electron by two means: photonic illumination and electron bombardment (i.e. the sum of the two excitations extracts the electron). In Dember’s initial study, he referred only to metals; however, more complex materials have been analyzed since then. The photoelectric effect due to the illumination of the metallic surface extracts electrons (if the energy of the photon is greater than the extraction work) and excites the electrons which the photons don’t have the energy to extract.