Search results

1

Ion Beam Induced Darkening in Tetrahedral Amorphous Carbon Thin Films

100%

Sandulov M., Berova M., Tsvetkova T., Zuk J.

Acta Physica Polonica A

|

2015

|

vol. 128

|

issue 5

953-956

EN

The samples of thin film (d ≈ 40 nm) tetrahedral amorphous carbon (ta-C), deposited by the filtered cathodic vacuum arc have been implanted with N⁺ at a fluence of 3×10¹⁴ cm¯² and ion energy E=20 keV. The induced structural modification of the implanted material results in a considerable change of its optical properties, best manifested by a significant shift of the optical absorption edge to lower photon energies as obtained from optical transmission measurements. This shift is accompanied by a considerable increase of the absorption coefficient (photodarkening effect) in the measured wavelength range (350÷2500 nm). These effects could be attributed to both the additional defect introduction and the increased graphitization, as confirmed by the X-ray photoelectron spectroscopy measurements. The optical contrast thus obtained (between implanted and unimplanted film materials) could be made use of in the area of high-density optical data storage using the focused ion beams.

2

Implantation Temperature Effects on the Nanoscale Optical Pattern Fabrication in a-SiC:H Films by Ga^{+} Focused Ion Beams

88%

Tsvetkova T., Wright C., Hosseini P., Bischoff L., Zuk J.

Acta Physica Polonica A

|

2013

|

vol. 123

|

issue 5

952-955

EN

This work is related to a novel approach of providing some new generation ultrastable (> 50 years), ultrahigh density (> 1 Tbit/sq.in.) data storage for archival applications. We used ion-implantation to write nanoscale data into hydrogenated amorphous silicon carbide (a-SiC:H) films. Wide bandgap a-SiC:H samples, Ga^{+} focused ion beam implanted, have been prepared. A range of samples has been focused ion beam patterned under different implantation conditions, with emphasis on different substrate temperatures (typically from 0C temperature to around room temperature). Some of the room temperature implanted samples were further annealed at + 250C in vacuum. The focused ion beam patterned samples were then analysed using near-field techniques, like atomic force microscopy, to define optimum implantation conditions and the resulting consequences for archival data storage applications. The atomic force microscopy analysis of Ga^{+} focused ion beam implanted a-Si_{1-x}C_{x}:H samples at room temperature and at 0C revealed an increase of both the depth and the width of the individual lines within the focused ion beam written patterns at the lower temperature, as a result of an increased ion beam induced sputtering yield, in good agreement with the previous results for the case of Ga^+ broad beam implantation in a-Si_{1-x}C_{x}:H and again suggesting that the best conditions for optical data storage for archival storage applications would be using Ga^+ ion implantation in a-SiC:H films with an optimal dose at room temperatures. Similarly, the atomic force microscopy results confirm that no advantage is expected to result from post-implantation annealing treatments.

3

Nanocrystal- and Dislocation-Related Luminescence in~Si Matrix with InAs Nanocrystals

76%

Komarov F., Vlasukova L., Milchanin O., Mudryi A., Zuk J., Pyszniak K., Kulik M.

Acta Physica Polonica A

|

2011

|

vol. 120

|

issue 1

204-207

EN

We have studied the influence of ion implantation and post-implantation annealing regimes on the structural and optical properties of silicon matrix with ion-beam synthesized InAs nanocrystals. (100) Si wafers were implanted at 25 and 500°C, subsequently with high fluences of As and In ions. After implantation the samples were processed by furnace and rapid thermal annealing at 900, 950 and 1050°C. A part of the samples implanted at 25°C was additionally exposed to H_2^{+} ions (100 keV, 1.2 × 10^{16} cm^{-2} in terms of atomic hydrogen). This procedure was performed to obtain an internal getter. In order to characterize the implanted samples transmission electron microscopy and low-temperature photoluminescence techniques were employed. It was demonstrated that by introducing getter, varying the ion implantation temperature, ion fluences and post-implantation annealing duration, and temperature it is possible to form InAs nanocrystals in the range of sizes of 2-80 nm and create various concentration and distribution of different types of secondary defects. The last ones cause in turn the appearance in photoluminescence spectra dislocation-related D1, D2 and D4 lines at 0.807, 0.870 and 0.997 eV, respectively.

4

Optical Pattern Fabrication in Amorphous Silicon Carbide with High-Energy Focused Ion Beams

76%

Tsvetkova T., Takahashi S., Sellin P., Gomez-Morilla I., Angelov O., Dimova-Malinovska D., Zuk J.

Acta Physica Polonica A

|

2011

|

vol. 120

|

issue 1

56-59

EN

Topographic and optical patterns have been fabricated in a-SiC films with a focused high-energy (1 MeV) H^{+} and He^{+} ion beam and examined with near-field techniques. The patterns have been characterized with atomic force microscopy and scanning near-field optical microscopy to reveal local topography and optical absorption changes as a result of the focused high-energy ion beam induced modification. Apart of a considerable thickness change (thinning tendency), which has been observed in the ion-irradiated areas, the near-field measurements confirm increases of optical absorption in these areas. Although the size of the fabricated optical patterns is in the micron-scale, the present development of the technique allows in principle writing optical patterns up to the nanoscale (several tens of nanometers). The observed values of the optical contrast modulation are sufficient to justify the efficiency of the method for optical data recording using high-energy focused ion beams.

5

Thermal Desorption Studies of Ar^{+} Implanted Silicon

64%

Drozdziel A., Wojtowicz A., Turek M., Pyszniak K., Maczka D., Slowinski B., Yushkevich Y., Zuk J.

|

vol. 125

|

issue 6

1400-1404

EN

Thermal desorption spectrometry measurements were performed for Ar implanted Si samples. Implantation energy E_{i} varied in the range 85-175 keV. The release of implanted Ar in two steps was observed in the temperature range 930-1300 K: the relatively narrow peak at lower temperature ( ≈ 930 K for implantation fluence 5 × 10^{16} cm^{-2}) is due to the release of Ar from the agglomerations (bubbles) while the broader peak observed for higher temperatures ( ≈ 950 K for implantation fluence 5 × 10^{16} cm^{-2}) comes from Ar atoms diffusing out of the sample. Inverse order of peaks is observed compared to the results for lower energy implantations (< 50 keV). Analyzing the thermal desorption spectra collected for different heating ramp rates enabled estimation of the desorption activation energy (2 eV for E_{i} = 85 keV and 1.7 eV for E_{i} = 115 keV).

6

Ion Beam Synthesis of InAs Nanocrystals in Si: Influence of Thin Surface Oxide Layers

52%

Komarov F., Vlasukova L., Milchanin O., Greben M., Komarov A., Mudryi A., Wesch W., Wendler E., Zuk J., Kulik M., Ismailova G.

Acta Physica Polonica A

|

2013

|

vol. 123

|

issue 5

809-812

EN

Nanosized crystallites have been synthesized in the Si and SiO_2/Si structures by means of As (170 keV, 3.2 × 10^{16} cm^{-2}) and In (250 keV, 2.8 × 10^{16} cm^{-2}) implantation at 25C and 500C and subsequent annealing at 1050C for 3 min. The Rutherford backscattering, transmission electron microscopy, and photoluminescence techniques were used to analyse the impurity distribution as well as the structural and optical characteristics of the implanted layers. It was found that oxidation of samples before thermal treatment significantly reduced the As and In losses. A broad band in the region of 1.2-1.5 μm was detected in the photoluminescence spectra. The highest photoluminescence yield for the samples after "hot" implantation and annealing was obtained. Anodic oxidation of the implanted samples before annealing results in the additional increase of photoluminescence yield.

Refine search results

Ion Beam Induced Darkening in Tetrahedral Amorphous Carbon Thin Films

Implantation Temperature Effects on the Nanoscale Optical Pattern Fabrication in a-SiC:H Films by Ga^{+} Focused Ion Beams

Nanocrystal- and Dislocation-Related Luminescence in~Si Matrix with InAs Nanocrystals

Optical Pattern Fabrication in Amorphous Silicon Carbide with High-Energy Focused Ion Beams

Thermal Desorption Studies of Ar^{+} Implanted Silicon

Ion Beam Synthesis of InAs Nanocrystals in Si: Influence of Thin Surface Oxide Layers