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Optical Interference Effects in Visible-Near Infrared Spectral Range for Arrays of Vertically Aligned Multiwalled Carbon Nanotubes

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Wąsik M., Judek J., Świtkowski K., Zdrojek M.

Acta Physica Polonica A

2017

vol. 131

issue 2

232-236

Based on the reflectance spectra for radiation wavelength from about 380 nm to 1.8 μm, the optical interference effects in vertically aligned multiwalled carbon nanotubes films are studied. We performed the measurements for two complementary polarization states of incoming radiation (s- and p-polarization) for nanotubes arrays sparse enough for interference effects to be possible to observe. By performing the measurements for different wavelengths and incidence angles, we mapped the evolution of interference maxima/minima of reflectance signal. The results from this novel approach indicate that for the radiation polarized perpendicularly to tubes axis (s-polarization), the real part of the effective refractive index can be estimated from the classic Fabry-Pérot model. In order to describe the differences between spectra obtained for s- and p-polarizations we discuss the most important factors that affect the reflectance signal in case of investigated nanotubes arrays.

Comparison of Ultrafast Photodetectors Based on N^+GaAs and LT GaAs

88%

Białous M., Mogilinski R., Wierzbicki M., Świtkowski K., Pura B.

Acta Physica Polonica A

2011

vol. 119

issue 3

382-386

We present investigation of a photodetector based on nitrogen-ion-implanted GaAs. Device photoresponse signal shows 1.15 ps FWHM (400 GHz, 3 dB bandwidth) with the voltage amplitude ≈ 1 mV, measured using a constructed electro-optic sampling setup with 80 fs width, 795 nm wavelength and laser pulses repetition rate of 80 MHz. Changes in the shape of electrical signal for different beam powers excitation and voltage biases have been demonstrated, compared with LT GaAs photodetector based on the same finger geometry. Using technique of X-ray diffraction and diffuse scattering analyses we have observed the decrease of lattice constant, radius of nanoclusters after implantation, respectively, and linear density dislocations increased over twice.

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2 Acta Physica Polonica A

1 2017

1 2011

2 Świtkowski K.

1 Białous M.

1 Judek J.

1 Mogilinski R.

1 Pura B.

1 Wierzbicki M.

1 Wąsik M.

1 Zdrojek M.

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Optical Interference Effects in Visible-Near Infrared Spectral Range for Arrays of Vertically Aligned Multiwalled Carbon Nanotubes

Comparison of Ultrafast Photodetectors Based on N^+GaAs and LT GaAs