Continuous Monitoring of Mg Oxidation by Internal Exoemission

Glass, Stefan; Nienhaus, Hermann

doi:10.1103/physrevlett.93.168302

Cited by 34 publications

(22 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using the logarithmic fit shown in the inset of Figure 20a, we obtain an attenuation length of 3.0 nm. This value is comparable to other values in the literature (e.g., the attenuation length (5.4 nm) in Mg/Si(111) that was measured after adsorption of oxygen 188,189 or other values for attenuation of chemically induced hot charge carriers). 11,86,87 …”

Section: Chemicurrent and Catalytic Activity Of M/tio 2 Nanodiodes (Msupporting

confidence: 89%

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

2015

View full text Add to dashboard Cite

Section: Chemicurrent and Catalytic Activity Of M/tio 2 Nanodiodes (Msupporting

confidence: 89%

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

2015

View full text Add to dashboard Cite

“…Electronic excitations have been found to be a general feature in the dissipation of gas-surface reaction energy. [1][2][3][4][5][6] In rare cases, they can be intense enough to generate electron or photon emission leading to exoemission and chemiluminescence. With the use of thinfilm electronic devices, e.g., Schottky diodes, the detection of low-energy excitations of electrons and holes in the metal has become feasible also for surface reactions without exoemission.…”

Section: Introductionmentioning

confidence: 99%

Electronic excitations in magnesium epitaxy: Experiment and theory

et al. 2010

View full text Add to dashboard Cite

The nonadiabatic response of the electronic system during growth of Mg films is investigated both experimentally by measuring chemicurrents in Mg/ p-Si͑001͒ Schottky diodes, and theoretically by time-dependent perturbation theory applied to first-principles electronic-structure calculations. Reverse currents are detected in the diodes when they are exposed to thermally evaporated Mg atoms. Dissipation of condensation energy to the electronic system as well as absorption of infrared photons due to heat radiation are the current-generating mechanisms. They can be distinguished by studying the dependence of the currents on the evaporator temperature and on the Mg film thickness. In contrast to the photocurrents, the chemicurrent is proportional to the Mg atom flux as it reproduces the enthalpy of Mg sublimation in an Arrhenius diagram. Independent measurements of photocurrents by use of an empty evaporator as a source of heat radiation provide further evidence for a chemicurrent contribution to the overall signal. The presence of chemicurrents in Mg epitaxy is further supported by simulations of monolayer growth and calculations of the pertinent rates for nonadiabatic electronic transitions in Mg adsorption. The simulations show that the grown surface is atomically rough with many step and kink sites. Adsorption at these sites is sufficiently exothermic to induce energetic electron-hole pairs that give rise to a detectable current across the Schottky barrier of the diode. The calculated spectra of the excited electrons and holes are found to display high-energy tails above 0.4 eV. While the contribution of the electronic channel to the dissipation of condensation energy is very small ͑less than 1%͒, the calculated probability for high-energy electronic excitations in Mg epitaxy is compatible with the chemicurrent contribution extracted from the experimental data.

show abstract

“…4 Chemicurrents are another example and are in focus of this study. 1,5,7 With the-compared to the usual metal work functions-low Schottky barrier ⌽ S , chemicurrents allow to detect electronic contributions to energy dissipation even for moderately energetic reactions. 1,5,7 With the-compared to the usual metal work functions-low Schottky barrier ⌽ S , chemicurrents allow to detect electronic contributions to energy dissipation even for moderately energetic reactions.…”

Section: Introductionmentioning

confidence: 99%

Chemical interaction of H and D atoms with Ag∕H:p-Si(111) thin film diodes

Krix¹,

Nünthel²,

Nienhaus³

2007

Journal of Vacuum Science & Technology A: Vacuum, Surfaces,

View full text Add to dashboard Cite

During exothermic reactions of atomic hydrogen or deuterium on a silver surface hot charge carriers are produced which have been observed by using Ag/ p-Si͑111͒ Schottky diodes. Thin film devices provide a means to bring a charge detector as close to the reaction site as the mean free path of the charge carriers. In the case of a p-doped substrate the Schottky barrier works as a high-pass energy filter for hot holes. The authors have therefore produced large area Schottky diodes with film thicknesses of up to 30 nm varying the thickness to rule out any influence of this device parameter. Those diodes were then exposed to beams of hydrogen atoms and deuterium atoms produced in a hot capillary source. Gas exposures do not affect the Schottky barrier height significantly. While exposing the samples to defined atom fluxes, the closed-loop current was monitored in real time. It shows that the current is proportional to the flux of atoms impinging on the surface. The authors have found hydrogen to generate 3.7 times more chemicurrent than is created during reactions with deuterium. Theoretical predictions of nonadiabatic energy dissipation using the electronic friction model agree well with the experimental results.

show abstract

Continuous Monitoring of Mg Oxidation by Internal Exoemission

Cited by 34 publications

References 20 publications

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

Electronic excitations in magnesium epitaxy: Experiment and theory

Chemical interaction of H and D atoms with Ag∕H:p-Si(111) thin film diodes

Contact Info

Product

Resources

About