Einstein and His Photoemission from Heavily Doped Quantum Wells

This paper explores the Einstein's Photoemission (EP) from Quantum wells (QWs) of Heavily doped (HD) nonlinear optical materials based on a newly formulated electron dispersion law considering all types of anisotropies of the energy band spectrum within the framework of k . p formalism in the presence of Gaussian band tails. We have also investigated the EP from QWs of HD III-V, II-VI, IV-VI, stressed Kane type compounds, Te, GaP, PtSb2, Bi2Te3, Ge and GaSb on the basis of newly derived respective E-k relation under heavy doping. We observe that the EP increases with increasing surface electron concentration and decreasing film thickness in spikey manners, which is the characteristic feature of such 2D structures and the numerical values are totally band structure dependent. The EP increases with increasing photo energy in a step-like manner for all the cases. The analyses for bulk HD materials have also been performed for the purpose of relative comparison. In the absence of band tails, all results get transformed to the well-known expression of photo-electric current density from non-degenerate semiconductors having parabolic energy bands and thus confirming then compatibility test. The most striking features are that the presence of poles in the dispersion relation of the materials in the absence of band tail creates the complex energy spectrum in the corresponding HD samples and effective electron mass exists within the band gap which is impossible without the concept of band tails.