Laser-Induced Growth of Titanium Nitride Microcolumns on Biased Titanium Targets

Titanium targets with a bias voltage ranging from −500 to +500 V were submitted to multipulse high repetition rate Nd:yttrium aluminum garnet (YAG; λ = 1.064 μm, τ ∼ 300 ns, ν = 30 kHz) laser irradiations in nitrogen at intensity values below the single-pulse melting threshold. The morphology of the TiN structures formed under the cumulative action of the laser pulses on the surface of the unbiased and biased targets was investigated by profilometry and scanning electron microscopy. Under these irradiation conditions, a specific columnar surface microrelief developed. The height of the microcolumns reached about 10–15 μm, and their diameter about 1–2 μm. The development of TiN microcolumns was enhanced by the applied bias voltage. The enhancement in the negative biased samples was stronger than that in the positive biased ones.

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Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

Materials ◽

10.3390/ma14123194 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3194

Author(s):

Adrian Petris ◽

Petronela Gheorghe ◽

Tudor Braniste ◽

Ion Tiginyanu

Keyword(s):

Harmonic Generation ◽

Nonlinear Optical ◽

Laser Pulses ◽

Third Harmonic Generation ◽

High Repetition Rate ◽

Third Order ◽

Third Harmonic ◽

The Third ◽

High Repetition ◽

Gan Crystal

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.

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Influence of Applied Bias Voltage on the Composition, Structure, and Properties of Ti:Si-Codoped a-C:H Films Prepared by Magnetron Sputtering

Journal of Nanomaterials ◽

10.1155/2014/937068 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Jinlong Jiang ◽

Qiong Wang ◽

Yubao Wang ◽

Zhang Xia ◽

Hua Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Magnetron Sputtering ◽

Bias Voltage ◽

Tribological Properties ◽

Structure And Properties ◽

Applied Bias ◽

Applied Bias Voltage ◽

Methane Mixture ◽

Composition Structure

The titanium- and silicon-codoped a-C:H films were prepared at different applied bias voltage by magnetron sputtering TiSi target in argon and methane mixture atmosphere. The influence of the applied bias voltage on the composition, surface morphology, structure, and mechanical properties of the films was investigated by XPS, AFM, Raman, FTIR spectroscopy, and nanoindenter. The tribological properties of the films were characterized on an UMT-2MT tribometer. The results demonstrated that the film became smoother and denser with increasing the applied bias voltage up to −200 V, whereas surface roughness increased due to the enhancement of ion bombardment as the applied bias voltage further increased. The sp3carbon fraction in the films monotonously decreased with increasing the applied bias voltage. The film exhibited moderate hardness and the superior tribological properties at the applied bias voltage of −100 V. The tribological behaviors are correlated to the H/E or H3/E2ratio of the films.

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