Role of hydroxyl groups in the formation of defect configurations in silicon devices

Abstract

We use density functional theory to investigate five types of neutral hydroxyl group (-OH) defect within bulk Si, in terms of structural and electronic properties. We find that two out of these five defect configurations yield degenerate n-type direct current conductivity and intra-band gap levels that lie in the vicinities of both the valence and the conduction bands. For the other three defect configurations, the defect bands appear near the valence band maximum (VBM) only and the Fermi level lies close to the mid-gap. Our results are generally consistent with the available experimental data on hydrogen-, oxygen- and hydroxyl-related defect states in bulk Si. More importantly, a few new fairly shallow donor-like states are predicted by our simulations in the VBM vicinity.

Plasma-induced reversible surface modification and its impact on oxygen heterogeneous recombination

“…The minimum kinetic energy of neutrals, E α , has been considered a free parameter and adjusted, so that the simulation results match closely the experimental data. The obtained value is E α = 0.29 eV (27.98 kJ•mol −1 ), well within the expected order of magnitude [36]. This value also matches the expectation that desorption of oxygen atoms from chemisorbed sites only takes place when T nw reaches approximately 2000 K [28].…”

“…We consider that the gas-phase particle needs a minimum kinetic energy E α to change the energy value of the chemisorption site. We expect E α to be of the order of the difference between defect energy levels for different configurations of silica lattice with OH radicals as defects, ∼0.3 eV [36]. For these low energies, we expect the flux of neutral particles from the gas phase to be much higher than the flux of O 2 ions [15].…”

Photoluminescence of oxygen vacancies and hydroxyl group surface functionalized SnO2 nanoparticles

“…From the literature it is clear that the conduction of oxides increases after formation of -OH groups on the surface and it forms donor states close to the conduction band. 18,23,24,41 The optical band gaps of samples A and B are found to be around 4.45 and 4.25 eV, respectively (Fig. 5).…”

“…Similarly, DFT calculations of -OH groups attached to Si surfaces revealed formation of donor defect states due to certain kind of Si-OH. 24 Based on various factors (e.g., season, temperature, location) moisture in atmosphere can vary from ca. 0.1 up to 4 vol%, which notably changes the electronic properties of the sensors and influences their sensitivity.…”

“…0.1 up to 4 vol%, which notably changes the electronic properties of the sensors and influences their sensitivity. 24 There are studies on the annealing effect on 'O' defects of the crystalline SnO 2 and desorption of 'O' with temperature. 14 In this context, there is lack of detailed investigation on the luminescence properties of the oxidation and desorption process of 'O' for quantum dots (QDs) and nanostructures of SnO 2 .…”