Team Focus

The research team focuses on the study of electronic and optical phenomena at surfaces and interfaces of nanomaterials caused by the impact of photons, ions, electrons and adsorption of gases for sensor applications, for the development of sources of light, and for the enhancement of the nano-diagnostic capabilities of analytical methods.

Current work

 Transport phenomena at the metal-semiconductor interface

Schottky contact is one of the key structures in semiconductor devices. Mechanism of formation of Schottky contacts on compound semiconductors has been the subject of long term investigation. High density of surface states and nonstoichiometric defects in compound semiconductors impedes the preparation of high quality Schottky diodes and substantially restricts the application potential of those materials.

Novel techniques of the preparation of thermally stable Schottky diodes have been developed by using the deposition of colloidal graphite and the electrophoretic deposition of metal nanoparticles (NPs). Our focus is on the theoretical and experimental analysis of the graphite/semiconductor and metal nanoparticles/semiconductor structures.

Figure 1: (a) SEM images of the graphite contact deposited on semiconductor substrate; (b) Cross section of the graphite/semiconductor Schottky diodes; (c) Raman spectrum of the graphite; (d) Comparison of the calculation results (solid lines) with the I-V characteristics  of graphite/CdMnTe diode measured at different temperatures (circles).

Figure 2: (a) Set-up of the electrophoretic deposition process; (b) Schematic cross-section of Pt NP/InP Schottky diodes; (c) I-V characteristics of the Pt NP/n-InP junctions in a semilogarithmic system of coordinates. The inset shows the temperature dependence of the rectification ratio determined at applied bias of 1V.

Relevant publications:

  1. Kosyachenko, L. A.; Yatskiv, R.; Yurtsenyuk, N. S.; Maslyanchuk, O. L.; Grym, J., Graphite/CdMnTe Schottky diodes and their electrical characteristics. Semicond Sci Tech 2014, 29 (1), 015006.
  2. Yatskiv, R.; Grym, J., Thermal stability study of semimetal graphite n-InP and n-GaN Schottky diodes. Semicond Sci Tech 2013, 28 (5), 055009.
  3. Yatskiv, R.; Grym, J., Temperature-dependent properties of semimetal graphite-ZnO Schottky diodes. Appl Phys Lett 2012, 101 (16), 162106.
  4. Yatskiv, R.; Grym, J.; Brus, V. V.; Cernohorsky, O.; Maryanchuk, P. D.; Bazioti, C.; Dimitrakopulos, G. P.; Komninou, P., Transport properties of metal–semiconductor junctions on n-type InP prepared by electrophoretic deposition of Pt nanoparticles. Semicond Sci Tech 2014, 29 (4), 045017.


Hydrogen sensors based on Schottky barriers

Hydrogen is nowadays widely used in medicine, chemical or automotive industry and is considered as a fuel of the future with a potential for the substitution of fossil fuels. However, it is highly volatile, extremely combustible, and its leak may cause explosion. Therefore, the development of hydrogen sensors with high sensitivity, short response time, low dimensions, and low production costs is of primary focus.

We have developed hydrogen sensors based on Schottky diodes fabricated by the deposition of colloidal graphite onto semiconductor surfaces functionalized with catalytic nanoparticles (Pt, Pd). These sensors are capable of detecting hydrogen in low concentrations down to 1 ppm.

Figure 3: Schematic cross-section of (a) Pt NP/InP and (c) graphite- Pt NP/InP  Schottky diodes;  SEM images of (b) thick layer and (d) submonolayer Pt NPs deposited on a semiconductor substrate by EPD; (e) Current transient characteristics of the graphite-Pt NP/ InP and Pt NP/InP the Schottky diodes under exposure to hydrogen.

Relevant publications:

  1. Grym, J.; Yatskiv, R., Schottky barriers based on metal nanoparticles deposited on InP epitaxial layers. Semicond Sci Tech 2013, 28 (4), 045006.
  2. Yatskiv, R.; Grym, J.; Zdansky, K.; Piksova, K., Semimetal graphite/ZnO Schottky diodes and their use for hydrogen sensing. Carbon 2012, 50 (10), 3928-3933.
  3. Zdansky, K.; Yatskiv, R., Schottky barriers on InP and GaN made by deposition of colloidal graphite and Pd, Pt or bimetal Pd/Pt nanoparticles for H-2-gas detection. Sensor Actuat B-Chem 2012, 165 (1), 104-109.
  4. Grym, J.; Prochazkova, O.; Yatskiv, R.; Piksova, K., Hydrogen sensors based on electrophoretically deposited Pd nanoparticles onto InP. Nanoscale Res Lett 2011, 6.


Synthesis and characterization of one-dimensional ZnO nanostructures

Low dimensional semiconductor structures have been intensively studied for prospective electronic and photonic applications. One of the key issues in these devices is to understand and control the charge transport at metal/semiconductor nanostructure interface. Our goal is to describe fundamental phenomena taking place during the charge transport in Schottky barriers prepared on one-dimensional ZnO nanostructures. Vertical arrays of ZnO nanorods (NRs) and nanowires (NWs) are characterized by a set of diagnostic methods as a feedback for the modification of technology in order to tailor their morphology and their electrical, optical, and structural properties. Schottky contacts to individual NRs and NWs and their arrays are formed by vacuum evaporation of metals, by the deposition of colloidal graphite, by e-beam lithography, by focused electron/ion beam induced deposition, and by the tip of atomic force microscope or by the nanomanipulator tip in the scanning electron microscope.

Figure 4: Heterojunction graphite/ZnO NRs: (a) Schematic diagram; (b) top view SEM image of the ZnO NRs; (c) SEM image of the ZnO NRs taken at 55° tilt; (e) I-V curves at different temperatures demonstrating the rectifying behavior of the heterojunction.

Relevat publications:

  1. R. Yatskiv, V.V. Brus, M. Verde, J.Grym, P. Gladkov: Electrical and optical properties of graphite/ZnO nanorods heterojunctions.  Carbon 2014, 77, 1011-1019.


Interaction of ions with solid surfaces

Ion beams are utilized both for the formation of nanostructures and for the chemical analysis of solid surfaces. We study physical and chemical processes initiated by ion bombardment of solid surfaces: sputtering, electron emission, implantation, ionization, formation of nanostructures. We influence those processes by injection of reactive gases, e.g., by oxygen. The understanding of those phenomena is important for correct interpretation of microscopic images of FIB and SIMS, for the improvement of analytical parameters of the SIMS technique or of its modern FIB SIMS variant, and for the development and exploitation of ion-induced formation of nanostructures.

Relevant publications:

  1. P. Williams, K. Franzreb, R. C. Sobers Jr, and J. Lorincik, “On the effect of oxygen flooding on the detection of noble gas ions in a SIMS instrument”, Nucl. Instrum. Meth. Phys. Res. B 268 (2010) 2758 – 2765.
  2. Z. Sroubek, J. Lorincik, "Kinetic electron emission from metal surfaces induced by impact of slow ions," Surf. Sci. 625 (2014) 7–9.
  3. P. Karmakar, G. F. Liu, Z. Sroubek, J. A. Yarmoff, Ion beam induced formation and interrogation of Au nanoclusters, Phys. Rev. Lett. 98 (2007) 215502 


Characterization of nanomaterials

For characterization of the studied materials we have a wide palette of analytical and microscopic techniques available at our institute - SEM, FIB, SIMS, EDX, AFM, STM, BEEM/BEES, Raman spectroscopy, optical microscopy, photoluminescence, cathodoluminescence, where three of them - BEEM/BEES, low temperature photoluminescence, and FIB SIMS we develop, improve or study in more detail. Additionally, in collaboration with other research teams at IPE or AS CR we exploit novel analytical methods targeted to the analysis of optical fibers, special glasses and semiconductor structures.

Relevant publications:

  1. J. Lorinčík, I. Kašík, J. Vaniš, L. Sedláček, J. Dluhoš, „Imaging of Dopant Distribution in Optical Fibers with an Orthogonal TOF SIMS", Surf. Interface Anal. (2014), in print, DOI: 10.1002/sia.5536
  2. J. Walachova, J. Zelinka, V. Malina, J. Vanis, F. Sroubek, J. Pangrac, K. Melichar, E. Hulicius, Ballistic electron emission spectroscopy/microscopy of self-assembled InAs quantum dots of different sizes embedded in GaAs/AlGaAs heterostructure, Appl. Phys. Lett. 92 (2008) 109904
  3. P. Gladkov, E. Hulicius, T. Paskova, E. Preble, K. R. Evans, Below band-gap optical absorption and photoluminescence excitation spectroscopy at room temperature in low-defect-density bulk GaN:Fe, Appl. Phys. Lett. 100 (2012) 031908

IPE carries out fundamental and applied research in the scientific fields of photonics, optoelectronics and electronics. In these fields, IPE generates new knowledge and develops new technologies.

Contact us

Data box: m54nucy

IČ: 67985882
DIČ: CZ67985882