Krzysztof Piotr Rola

Lukasiewicz Research Network – PORT Polish Center for Technology Development · Materials Technology Laboratory

Sol–gel materials based on SiO2 and TiO2 precursors are attractive as a new platform for planar photonics. Particularly interesting are those based on organically modified silica (ORMOSIL), which may improve the luminescent properties of organic dyes. However, their microstructurization remains a challenge as it requires optimization of various tec...

MAPbBr 3 perovskites are known for bright green surface emission. We utilize the micromachining and nanofabrication tools to alter the photoluminescence properties of this perovskite and create fluorescent patterns and diffraction or resonant nanostructures.

HYPHa project is a joint venture to develop a low-cost integrated photonics platform based on silica-titania materials deposited via a sol-gel method and a dip-coating procedure. The dip-coating technique is cost-effective and makes it possible to produce high-quality and low-loss silica-titania thin films on glass or buffered silicon substrates. F...

Composite silica-titania waveguide films of refractive index ca. 1.8 are fabricated on glass substrates using a sol-gel method and dip-coating technique. Tetraethyl orthosilicate and tetraethyl orthotitanate with molar ratio 1:1 are precursors. Fabricated waveguides are annealed at 500 °C for 60 min. Their optical properties are studied using ellip...

The high-energy electrons can induce significant physicochemical changes in ionic liquids (ILs), of which polymerization and solidification are particularly interesting due to potential application in microstructures fabrication using electron beam (EB) patterning. However, the role of allyl and alkyl substituents of cation in these phenomena is no...

In this work the fabrication of fluorescent microstructures through the e-beam induced solidification of two types of room temperature ionic liquids (RTILs) with fluorescent organic dyes is reported. It is shown that, by introducing dual-step e-beam patterning method with controlled accelerating voltage, solid micro-sized reservoirs are fabricated...

Single crystals of the filled skutterudite compound ThOs4As12 were grown by a Cd:As flux method. Low-temperature specific-heat measurement reveals a very small Sommerfeld coefficient of the electronic term γ=3.4(3) mJ/mol K2, indicative of a semiconducting or semimetallic character of ThOs4As12. A low electronic density of states at the Fermi level...

Planar photonic components can be fabricated with high resolution by electron beam patterning of polymer thin films on solid substrates such as silicon or glass. However, polymer films are normally formed by spin-coating of lithographic resists containing not only polymers but also volatile solvents, which is a serious environmental and health issu...

The syntheses and full spectral (NMR, MS, IR), thermal (DSC) and ion chromatographic characterization of two series of amine-derived ionic liquids bearing 4-vinylbenzyl substituent and having chloride or bis(trifluoromethanesulfonyl)amide anion have been presented. The analysis of the dependence between ¹ H NMR chemical shift value of selected prot...

We report the new fluorescent polymerizable imidazolium-based ionic liquids for photonics application. We investigate two approaches: one ionic liquid (IL) contains the active fluorescein dianion as an intrinsic part of the polymerizable ionic liquid structure. The second liquid is based on the mixture of polymerizable ionic liquid with optically a...

The electron beam patterning is an important technology for fabrication of miniaturized photonic devices. The fabrication process conventionally involves usage of radiation sensitive polymer-based solutions (called resists). We propose to replace typical polymer resists with eco-friendly solvent-free room-temperature ionic liquids (RTILs), which ar...

Tensioactive compounds, such monohydric or polyhydric alcohols cause that with an increase in their concentration in solutions, surface tension at the liquid-gas interface – γLG and wetting angle at the interface silicon-solution – θLS decrease. It means that on both the surfaces an adsorption layer of the alcohol occurs. It results in lowering of...

The etching process of monocrystalline silicon in potassium hydroxide solution with addition of Triton X-100 surfactant at different temperatures is studied. It is shown that decreasing the temperature lowers etch rates and improves surface morphology of Si (hkl) planes. Based on Arrhenius plots of etch rates, activation energies for Si (100) and (...

The study concerns anisotropic etching of silicon (1 0 0) and (1 1 0) planes in potassium hydroxide aqueous solutions saturated with different monohydric alcohols (C3H7OH, C4H9OH and C5H11OH). The main goal of the research is to systematically examine the influence of length and branching of alcohol molecules alkyl chains on etching process. The et...

The molecular modelling was be applied in order to calculate the work of adhesion between solutions of water, isopropyl alcohol (IPA) and silicon. The work of adhesion was calculated by using two computational methods based on experiment as well as numerical simulations. The method of wetting angle in case of the molecular modelling was used in ord...

The fabrication of 45° micromirrors by silicon anisotropic etching in potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH) solutions containing organic additives is investigated in this paper. The reflective planes are formed by {110} sidewall planes inclined at 45° towards the Si (100) wafer. Isopropyl alcohol and Triton X-100 surfac...

Anisotropic etching of Si (100) and (110) planes in alkaline solutions containing the nonionic surfactant is studied in this paper. Triton X-100 surfactant, normally used for the modification of TMAH (tetramethylammonium hydroxide) etchant, is added to KOH (potassium hydroxide) solution. As a result, the (100) and (110) etch rates are significantly...

Wet chemical etching of Si(1 0 0) and Si(1 1 0) wafers in TMAH solutions containing Triton X-100 and alcohol additives was studied in a wide range of alcohol concentrations. TMAH solutions containing butanol-2 and ternary solutions composed of TMAH + Triton + alcohol, used in the experiments, had not been investigated before. The phenomena associat...

The results of etching of silicon surfaces with different crystallographic orientations in KOH solutions containing a nonionic surfactant Triton X-100 are presented in this paper. The etch rate ratio R(100)/R(110) >1, typical of KOH + IPA and TMAH + Triton X-100 mixtures, is achieved. The surface morphology of Si(hkl) wafers is closely investigated...

The paper deals with wet chemical anisotropic etching of Si(hkl) wafers in KOH solutions containing isopropyl alcohol. The impact of KOH and alcohol concentrations on the etch rates of (hkl) planes is shown. The effect of KOH concentration in pure KOH solutions resembles the one in KOH solutions non-saturated with alcohol and is different from the...

Anisotropic etching process of Si (100) and (110) planes in low concentrated potassium hydroxide (KOH) solutions containing Triton X-100 surfactant is studied in this paper. Addition of a little amount of the surfactant to the etchant considerably reduces etch rates of both the planes, though the etch rate ratio R(100)/R(110) > 1 is obtained. The (...

In this work, results of measurements of surface tension of KOH and TMAH solutions containing alcohol additives were used to assess the behavior of the alcohols during silicon anisotropic etching. Surface tension of KOH and TMAH solutions containing additives of alcohols with one or more hydroxyl groups as well as etching rates and surface roughnes...

In this paper we presented results of adsorption energy using molecular dynamics methods and comparison with contact experiment with 3% solution of IPA (isopropyl alcohol) and water on the silicon wafer. Two methods of surface energy of numerical calculation were applied in the presented research. The first one was based on obtaining surface energy...

The possibility of fabrication of micromirrors inclined towards silicon substrate at 45 degrees is studied. The 45 degrees micromirrors are formed by {110} sidewall planes in the Si (100) wafer by anisotropic etching in alkaline solutions containing surface active compounds such as Triton X-100 surfactant and isopropyl alcohol. The quality of {110}...

Random pyramid texturization of Si(1 0 0) substrates in alkaline solutions with addition of surface active compounds is considered. Technological difficulties connected with the application of alcohol additives are analyzed and a new solution for the wet-chemical texturization is proposed. The commonly applied alcohols in the texturization process,...

The influence of alcohol concentration on etch rate and surface morphology of (100) and (110) Si planes was investigated in this paper. The etching processes were carried out in KOH solutions with different concentrations of isopropanol and butanols. The etch rate minima versus alcohol concentration were observed for all the alcohols used in the ex...

In this paper the process of silicon anisotropic etching in KOH solutions containing isopropyl alcohol in a wide concentration range is extensively studied. Though the alcohol does not take part in the etching process itself, it strongly affects the etching results. Both etch rates and the roughness of etched surfaces depend on the alcohol concentr...

Anisotropic etching of silicon in KOH solutions saturated with tertiary-butyl alcohol (tert-butanol) was studied in this paper. The influence of KOH concentration of the solution with tert-butanol on Si(1 0 0) surface roughness and convex corners undercut were examined. It was shown that the largest reduction of convex corner undercut is achievable...

Fabrication of micromirrors inclined at 45° towards substrate is studied in this paper. The micromirrors are fabricated by anisotropic etching of monocrystalline silicon in KOH aqueous solutions saturated with different alcohols. The micromirror is formed by {110} sidewall inclined at 45° towards {100} substrate. The influence of propyl and butyl a...

The influence of alcohol additives on etch rate anisotropy of Si(hkl) planes has been studied. The etching processes were carried out in 3 and 5 M KOH aqueous solutions saturated and non-saturated with alcohols. Isopropanol, 1-propanol and tert-butanol were examined. It has been showed that the etching process cannot be controlled only by the surfa...

A study of manufacturing micromirrors inclined at 45° towards silicon substrate has been presented in this paper. The micromirrors can be formed by {100} or {110} sidewall planes etched in (110) or (100) Si substrates in alkaline solutions. The smoothness of the surface and etch rate anisotropy are crucial parameters of fabricated structures. The r...