First principles electronic structure of coincidence site epitaxial Ag/Si(111) interface

Abstract

Ag/Si(111) heterojunction having $25% lattice mismatch can be formed by placing four surface unit cells of Ag(111) on three surface unit cells of Si(111), thereby reducing the effective strain in the Ag film to $0.3% in this coincidence site epitaxial growth. We have carried out first-principles investigation of such Ag/Si(111) interface to establish the interplay between the structural and electronic properties. While the Ag overlayer affects the reconstruction of the Si(111) surface, we find that the geometrical relaxation of the Ag atoms is influenced by the subsurface Si-layer and the concomitant lattice mismatch. The electronic density of states show some oscillations near the Fermi energy, which have been compared with the scanning tunnelling spectroscopic (STS) experimental data. The signature of metal-induced gap states (MIGS) for this metalsemiconductor heterojunction has been established from the evolution of localized gap states in the layer projected density of states. Our DFT estimated work function values for Ag(100), (110) and (111) have an excellent agreement with the available experimental results. Also, the p-type Schottky barrier height (SBH) of this rectifying Ag/Si contact has been calculated from the Kohn-Sham estimates of E F À E v modified by the interface induced dipole.

Electronic structure in the crossover regimes in lower dimensional structures

“…The trend of evolution is in reasonable agreement with the free electron model, Fig. 11 [17,18]. The change of the values of L x , L y and L z amounts to change of electron density, which affects DOS.…”

“…The electronic DOS in the Ag system is influenced by the proximity of Si across the interface [18]. Also Ag induces metal induced gap (MIG) states within the band gap of Si [18]. However, our free electron model appears to agree with the observed trend in the 0-D to 2-D crossover regime.This trend is shown by the smooth line in Fig.…”

“…The detailed comparison is not possible between experiment and the free electron model also for other reasons, such as, deviation of effective mass from the free electron mass and the proximity effect. The electronic DOS in the Ag system is influenced by the proximity of Si across the interface [18]. Also Ag induces metal induced gap (MIG) states within the band gap of Si [18].…”

Plasmon-induced charge separation: chemistry and wide applications

“…It must be noted that the real value of the barrier height often deviates from the simple theoretical estimation. 25 …”

Mechanistic Analysis of Plasmon-Induced Charge Separation by the Use of Chemically Synthesized Gold Nanorods

“…The E b value used for the best fit, 0.87 eV, is still lower than the theoretical energy threshold (1.2–1.57 eV). It was reported that the work function of Au nanoparticles and Schottky-barrier height at the interface between a Au nanoparticle and an n-type semiconductor are smaller than those for bulk Au. , In addition, the Schottky-barrier height often deviates from the theoretical value by several hundreds of millivolts . Actually, a photopotential response was observed upon 900 nm light irradiation (ca.…”