Low temperature scientific luminescence laboratory
Dr hab. Jacek Polit prof. UR - Laboratory Manager
Mgr Renata Wojnarowska
MSc. Kinga Maś
The aim of the laboratory is to measure luminescence parameters and to determine energy states at low temperatures of 4,2K low-dimensional structures
LOW-TEMPERATURE LUMINESCENCE SCIENCE DEPARTMENT
It allows for precise quality control of the received low-dimensional structures by analyzing the position of the energy states from which the doping level and its distribution can be determined.
The main components of the station are a laser with a wavelength of 680 nm and a power of 100 mV. The laser power is controlled by a shutter. Cryostat with sample holder for measuring at temperatures up to 4.2 K, microscope lens, HORIBA HR 550 monochromator with diffraction gratings up to 1500nm with the number of scratches from 150 mm to 900 pixels per mm. Camera preview set of lenses and filters. Illumination of the sample, a set of lenses and filters. And a computer set containing a specialized control program. The system is located on an anti-vibration optical table.
As a result of the measurements, luminescence intensity curves are obtained from the position. From the position and shape of the curve, the energy structure of the samples under investigation is estimated.
The result of the luminescence curve for a structure containing GaAs.
PUBLISHING DISTINCTION for 2014 - 2017 Laboratory staff Low Temperature Luminescence.
1) M. Marchewka M. Woźny,J. Polit, A. Kisiel, B. V. Robouch,A. Marcelli, and E. M. Sheregii, The stochastic model for ternary and quaternary alloys: Application of th Bernoulli relation to the phonon spectra of mixed crystals Journal of Applied Physics 115, pp.114903-1 114903-15 (2014)
2).R. Wojnarowska, J. Polit, D. Broda, M. Gonchar, and E. M. Sheregii, Surface enhanced Raman scattering as a probe of the cholesterol oxidase enzyme. Applied physics letters 106, pp 103701-1 103701-4, (2015).
3) .R. Wojnarowska, J.Polit D. Broda, M. Gonchar, E M.Sheregii, Gold nanoparticles like a matrix for covalent immobilization of cholesterol oxidase – Application for biosensing. Archives of metallurgy and materials, 60,pp.2289-2295, (2015)
4) .G. Tomaka J. Grendysa ,P.Śliż,C.R. Becker, J.Polit,R. Wojnarowska, A.Stadler and E.M. Sheregii, High –temperature stability of electron transport in semiconductors with strong spin- orbital interaction, PHYSICAL REWIEW B 93, 205419 (2016).
5). J.Polit ,M. Wożny , J. Cebulski M. Marcelli , M. Piccinii and E.M.Sheregii , Role of electron – phonon interaction in the temperature dependence of the Phonon mode frequency in the II- VI compound alloys, Phys. Stat. Sol.C,13, 510- 513 , (2016)
6) Andriy I. Savchuk, Ihor D. Stolyarchuk , Serhii A. Savchuk , Eugeniusz M. Sheregij , and Jacek Polit Structural, optical and magnetic characteristics of II-VI semiconductor nanocrystal-graphene hybrid nanostructures Phys. Status Solidi C 13, No. 7–9 (2016) 519
7) R. Wojnarowska-Nowak, J.Polit, A. Zięba, I.D.Stolyarchuk, S.Nowak, M. Romerowicz-Misielak, E.M. Sheregii, Colloidal quantum dots conjugated with human serum albumin-interaction and bioimaging properties Opto- Electronics Review, 25, 137-145 (2017)
Under this topic, a methodology has been developed to determine the concentration of cholesterol oxidase enzyme, which is one of the most important analytical enzymes. Raman scattering was obtained from choresterol oxidase using 16-mercaptohexadecanoic acid linker with gold nanoparticles. This allowed for surface plasmon resonance. PO lines of V and C = C are assigned to Flawin groups. This means that there is a stable binding of the enzyme to nanoparticles. Figure 1 shows the Raman spectra obtained.
FIG. 1. Raman spectra of (a) AuNPs; (b) AuNPs linked with MHDA; and (c) AuNPs conjugated via the MHD linker with ChOX.
Table 1 shows the identification of Raman lines
Identification of Raman lines from fig.1.
Figure 2 shows Raman spectra of choresterol oxidase with nanoparticles of different sizes
FIG. 2. Raman reflectance spectra of ChOX immobilized on the nanoparticles of different size: (a) 42 nm,(b) 55 nm, and (c) 80 nm.
Another element of the subject was bioimaging with the use of CdCoS quantum dots associated with human serum albumin (HSA).
Fig.3 Illustration of CdCoS + HSA quantum dot formation.
Figure 4 shows AFM images of CdCoS quantum dots and CdCoS + HSA.
Rys.4 Fig. AFM images of the pure CdCoS QDs (A), pure HSA (B), QDs after interaction with HSA: 2D topography (C), and 3D image (D)
Figure 5 shows the Raman spectra of CdCoS quantum dots.
Fig.5 Raman spectra of CdCoS quantum dots and its interpretation.
Figure 6 presents the FTIR spectrum and its interpretation of quantum dots and their complexes
Fig.6. FTIR spectra of the HSA (blue), HSA after interaction with: CdTe QDs (red) and CdCoS QDs (green)
As part of the bioimaging, the synthesis and characterization of CdTe nanocrystals that are albumin-treated as a fluorescent probe
Figure 7 depicts photoluminescent spectrum of CdTe quantum dots and CdTe + HSA bionanocomplex.
Fig. 7. Photoluminescence (PL) spectra of CdTe NCs solution, and CdTe NC-HSA bionanocomplexes with different concentration of HSA: 6.5; 15; 30×10-6 M.
Figure 8 depicts photoluminescent spectrum of CdTe quantum dots and CdTe + HSA bionanocomplex.
Fig. 8 FTIR spectra of the CdTe NCs (black), HSA (blue), HSA after interaction with CdTe NCs (red).
Interpretation of FTIR spectra is shown in Table 2
Identification of the lines observed in the FTIR spectra of HSA (Fig. 5); s-strong, m-medium, w-weak
Electron-Fonon interaction is another subject in which low-temperature luminescence laboratory workers are involved.
Within this subject, the temperature dependence of the TO phonon frequency in solid solutions based on HgTe of the semiconductor compounds II -VI was investigated. As an example, a three-component solid solution Hg0.9Zn0.1Te can be given which has demonstrated the discontinuity of the frequency dependence of the HgTe-TO-like and ZnTe-TO -like.
Analogously to the Hg0.885Cd0.115Te system that was observed for the first time and described in [Sheregii et al., Phys. Rev. Lett. 102, 045504 (2009)]. Theoretical generalization of the temperature shift of the phonon frequency in the analytical equation, there is an anharmonic contribution of the electron-phonon interaction.
Solid solutions Hg0.885Cd0.115Te and Hg0.9 Zn0.1Te contain Dirac point
( Γ 6- Γ8 = 0).
Figure 9 shows the temperature dependence of the reflection spectrum
Fig.9 Reflectivity R(ω,Τ) for Hg0.9 Zn0.1Te in frequency region from 80 cm-1 to 220 cm-1 and the temperature interval of 30-300 K.
Rys. 10 The frequency positions of ZnTe like (a) and HgTelike (b) subband maxima on the Im[ε(ω,T)] curves for the Hg0.9 Zn0.1Te at different temperatures in the range of 30-300 K.