The surface and materials science of tin oxide

Unencapsulated, exfoliated black phosphorus (BP) flakes are found to chemically degrade upon exposure to ambient conditions. Atomic force microscopy, electrostatic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy are employed to characterize the structure and chemistry of the degradation process, suggesting that O2 saturated H2O irreversibly reacts with BP to form oxidized phosphorus species. This interpretation is further supported by the observation that BP degradation occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) versus hydrophilic SiO2. For unencapsulated BP field-effect transistors, the ambient degradation causes large increases in threshold voltage after 6 h in ambient, followed by a ∼103 decrease in FET current on/off ratio and mobility after 48 h. Atomic layer deposited AlOx overlayers effectively suppress ambient degradation, allowing encapsulated BP FETs to ma...

Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation

Characterization of amorphous and nanocrystalline carbon films

This paper revies the preparation and properties of hard forms of amorphous carbon and hydrogenated amorphous carbon, often known as diamond-like carbon. Properties such as the hydrogen content, sp 3 content, optical gap, refractive index, hardness, elastic modulus and friction and their dependence on the deposition conditions are described. Models of the electronic structure and mechanical properties are used to relate the physical properties to the atomic structure.

Properties of diamond-like carbon

Hard amorphous (diamond-like) carbons

The C KLL spectra from natural diamond, graphite, and single‐crystal β‐SiC have been investigated using x‐ray photoelectron spectroscopy and first‐derivative x‐ray excited Auger electron spectroscopy (XAES). It is shown that the XAES spectra is essentially the same as that obtained with conventional AES with the added benefits of no electron beam (e‐beam) damage, enhanced fine structure, and the simultaneous acquisition of the C 1s and valence‐band spectra. The C KLL XAES fine structure provides a fingerprint of the carbon bonding state and the C 1s and valence‐band spectra provide insight into the origin of this fine structure. Diamondlike carbon films fabricated by hydrogen gas reactive sputtering of graphite on Si were also investigated. The XAES C KLL spectra in conjunction with the valence‐band spectra verifies the tetrahedral C–C bonding in these films even though the AES spectra shows a graphitelike structure; indicative of e‐beam damage.

The C KLL first‐derivative x‐ray photoelectron spectroscopy spectra as a fingerprint of the carbon state and the characterization of diamondlike carbon films

Comparison of the CKLL first-derivative auger spectra from XPS and AES using diamond, graphite, SiC and diamond-like-carbon films

Esca studies of Ga, As, GaAs, Ga2O3, As2O3 and As2O5

Long-time air oxidation and oxide-substrate reactions on GaSb, GaAs and GaP at room temperature studied by X-ray photoelectron spectroscopy

A fine-powdered sample of high purity SnO2 gave a strong ESR signal (gav≈1.90) after reduction in vacuum. This BSR center, like the g≈1.96 center of ZnO, is associated with the n-type conduction. When the sample was exposed to O2 or H2, the spin concentration, the full half width and also the electric conductance were changed. These variations are well explained by assuming that the fine-powdered SnO2 has double donor centers originated from both bulk and surface oxygen vacancies, The gav≈1.90 center may be due to the un-ionized deep donor electrons trapped in the surface oxygen vacancy.

https://iopscience.iop.org/article/10.1143/JJAP.14.779/pdf

Yusuke Mizokawa

Papers

The C KLL first‐derivative x‐ray photoelectron spectroscopy spectra as a fingerprint of the carbon state and the characterization of diamondlike carbon films

Comparison of the CKLL first-derivative auger spectra from XPS and AES using diamond, graphite, SiC and diamond-like-carbon films

Esca studies of Ga, As, GaAs, Ga2O3, As2O3 and As2O5

Long-time air oxidation and oxide-substrate reactions on GaSb, GaAs and GaP at room temperature studied by X-ray photoelectron spectroscopy

ESR and Electric Conductance Studies of the Fine-Powdered SnO2