Local bonding effect on the defect states of oxygen vacancy in amorphous HfSiO4

A variety of materials containing many different microstructures have been examined with the USS MVEM. Three topics have been selected to illustrate some of the more recent studies of diffraction phenomena and defect, grain and multi-phase structures of metals and minerals.(1) Critical Voltage Effects in Metals and Alloys - This many-beam dynamical diffraction phenomenon, in which some Bragg resonances vanish at certain accelerating voltages, Vc, depends sensitively on the spacing of diffracting planes, Debye temperature θD and structure factors. Vc values can be measured to ± 0.5% in the HVEM ana used to obtain improved extinction distances and θD values appropriate to electron diffraction, as well as to probe local bonding effects and composition variations in alloys.

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Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen

MRS Proceedings ◽

10.1557/proc-766-e8.5 ◽

2003 ◽

Vol 766 ◽

Author(s):

V. Ligatchev ◽

T.K.S. Wong ◽

T.K. Goh ◽

Rusli Suzhu Yu

Keyword(s):

Deep Level ◽

Dielectric Films ◽

Silicon Substrates ◽

Reverse Bias Voltage ◽

Defect States ◽

Single Side ◽

Sandwich Type ◽

Transient Spectroscopy ◽

P Type ◽

Spectrum Deconvolution

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.

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Impact Of Synthesis Route on the Water Oxidation Kinetics of Hematite Photoanodes

10.26434/chemrxiv.12505742.v1 ◽

2020 ◽

Author(s):

Camilo A. Mesa ◽

Ludmilla Steier ◽

Benjamin Moss ◽

Laia Francàs ◽

James E. Thorne ◽

...

Keyword(s):

Oxygen Vacancy ◽

Reaction Kinetics ◽

Water Oxidation ◽

Oxidation Kinetics ◽

Oxidation Reaction ◽

Charge Accumulation ◽

Optical Signals ◽

Current Voltage ◽

Voltage Performance ◽

Kinetics Of

<p><i>Operando</i> spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.</p>

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