THE IMPACT OF ADSORBED MONOLAYERS WITH AN ARBITRARY CONCENTRATION RATIO OF OPPOSITE CHARGES ON THE ELECTRON AFFINITY OF A SEMICONDUCTOR

Abstract

A dipole layer on the semiconductor’s surface with the equal concentration of oppositely charged adsorbed atoms (e. g., oxygen and metal) Ns(-) = Ns(+) can decrease the electron affinity by up to 3 eV. The  analytical part of this paper demonstrates that the asymmetry in the surface concentration of oxygen  and metal can impact the affinity in two ways: when Ns(-) > Ns(+), the affinity’s decrease is lower due to  upward bending of the bands in the region of the space charge of the semiconductor, while when Ns(-) < Ns(+) the affinity’s decreases greater due to the downward bending of the bands. Such impact is desirable as it facilitates fabrication of surfaces with low work function for modern emission electronic devices.