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Institute for Nanotechnologies of the International Conversion Foundation (INAT ICF)

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«UMKA» LABORATORY NANOTECHNOLOGICAL COMPLEX
based on scanning tunneling microscope

The cherished desire of scientists (and not only scientists) in course of many years is to observe behaviour of separate atoms at the surface directly and to study processes involving single atoms or small groups of atoms. That is why physics of surface phenomena is one of fields of science developing most intensively nowadays. In particular, successes of modern micro- and nanonelectronics, heterogeneous catalysis, space technologies, etc. are based on studies in the field of physics of surface of solids. Studying miscellaneous electronic, atomic and molecular processes taking place at the surfaces of bodies remains actual due to it.

Scanning tunneling microscopes (STM) give researchers such an opportunity. Modern domestic «Umka» nanotechnological complex produced by ICF Institute for Nanotechnologies based on STM developed by it occupies a special position among them.

«Umka» NTC is not only a wonderful instrument for training in the field of practical methods of work with nanoscaled structures. It is also used in university and scientific laboratories successfully for studies in the field of physics, chemistry, biology, medicine, material science and other fundamental and applied sciences. Besides, application of offered «Umka» NTC in control systems of high technology industrial enterprises and organizations dealing with control of products quality and state of environment is a prospective field.

«UMKA» NANOTECHNOLOGICAL COMPLEX POSSESSES
THE OPTIMAL PRICE-TO-QUALITY RATIO
 

 

НАВИГАЦИЯ ПО СТРАНИЦЕ

«UMKA» laboratory nanotechnological complex (NTC) has been developed and is produced by self-governing non-profit organization «Institute for Nanotechnologies of the International Conversion Foundation (INAT ICF)» based on «Umka-02-U» scanning tunneling microscope developed by the Institute and modified in 2010.

THE PURPOSE OF THE DEVICE

 «Umka-02-U» scanning tunneling microscope (STM). which is a part of «Umka» NTC (Fig.1), is a probe microscope used for studying properties of materials and surface topography at atomic- molecular level with non-destructive method. Studying both conductive and low conductivity materials (including biological objects and their fragments of size up to 5-6 μm) as well as semiconductors can be fulfilled with the help of "Umka-02-U" STM in air atmosphere. This feature distinguishes it from the previous modifications.
Fig.1.

Functional opportunities

The device allows:
  • determination of surface topology of samples in the form of sharp 2D- и 3D-images with atomic resolution;
  • determination of work function and impedance (determination of admixtures in the studied material); measuring current-voltage and differential characteristics of the material (determination of conductivity type of the material, analysis of structure of conductive and magnetic samples) at atomic-molecular level;
  • determination of admixtures in the studied material;
  • measuring profile parameters (roughness, dimensions of inclusions and nanoparticles);
  • measuring all types of differential spectra: dI/dU, dI/dH, dH/dU (applied data processing algorithms allow determination of amplitude and phase shift between measurement channels). It provides an opportunity of using the complex at studying corrosion, including heterogeneous materials, allowing clear determination of structure of "grains" of various composition, studying composite materials, distinguishing between areas of different conductivity type and alloying level in semiconductors.
  • performing in situ evaluation of long term external impact upon samples (determination of corrosion resistance, radiation impact , etc.).
Besides, "Umka" NTC allows fulfilling works, which demand determination of characteristics of materials and media at atomic-molecular level and fulfilling their analysis (including analysis of condition of coatings and surfaces of treated details; studying electro conductive surfaces, corrosion, etc.).

DESCRIPTION OF THE DEVICE

Principle of operation

"Umka-02-U" scanning tunneling microscope is the basis of "Umka" nanotechnological complex. This STM model designed and put into production in 2010 is the further development of STM line created in INAT ICF. As regards its functional opportunities, it unites already known "Umka-02-Е" STM (basic model for training) and "Umka-02-L" STM (intended for low conductivity materials and biological objects).
СТМ "Умка-02-U" is a small and compact device (Fig.1), which can be connected to PC and can be controlled by it. It facilitates working with data and their processing essentially. The modern computer allows in-situ image processing, e.g., obtaining 3D images of surfaces, turning them at various angles, varying their colors, using various graphic effects, etc.
Operation principle of tunneling microscope differs significantly from all other microscopes and is based on quantum nature of particles. Its operation is based on tunneling effect, i.e. phenomenon of tunneling of electrons through a narrow potential barrier between metallic probe and sample in external electric field. STM fulfils detecting of local interaction (current value variation) occuring between the probe and studied sample surface at their mutual approach. Electric current occurs in the circuit consisting of the needle (probe), sample anв voltage supply. Data on material and surface topography are obtained at varying distance between the sample and the needle (decreasing tunnel gap) or at varying tunnel current value. Surface images up to atomic resolution can be obtained with the help of STM.
Fig.2.
1 – Probe; 2 – Piezoelectric motor;
3 – Tunnel current amplifier; 4- Feedback module; 5 – Sample; 6 – Voltage supply.
The scheme is as follows (Fig.2). A low voltage is applied between the probe (1) and studied sample. Applied voltage value should correspond to the barrier value. Ion emission can occur instead of tunnel current if applied voltage is too high. Microscope probe, which is fixed at piezomotor (2), moves upon the sample without touching it. It moves along the lines, i.e., it scans the sample (5) and forms the full frame. The number of scan lines depends on the required image (scan) resolution. Tunnel current enters feedback module (4), which controls probe movement, after having passed the amplifier (3). 
Probes made of tungsten wire and sharpened to the size up to 30 nm are used in «Umka-02-U» STM. Probes are manufactured by electrochemical etching method with the help of a special  device for sharpening probes developed by INAT ICF.
Requirements to studied sample:
  • flat square plate (10 mm length approximately);
  • smooth surface;
  • electro-conductive or low-conductivity material or semiconductor (the corresponding substrate should be selected for biological objects).
The probe is located horizontally in "Umka-02-U" STM (Fig. 3). The sample is located on guides at some distance from the probe tip. Automatic approach is launched after that. Approach is fulfilled with the help of piezoceramic tube elements.
Two piezoelectriс motors are used in STM for controlled displacement of the needle at super small distance. They are intended for ensuring precision mechanical scanning of studied sample by the probe. The sample is approached to the probe with the help of raw positioning system.
Tunnel current occurs in the circuit during approach. Soft approach begins as soon as current takes particular value.
This scheme provides automatic precise positioning of the sample and prevents the probe from «sticking» into the surface of the sample.


Fig 3.

Technical characteristics:

Resolution
Atomic, molecular
Sample dimensions (mm)
8 х 8 х (0,5÷4,0)
Scanning area (μm)
6 х 6 ±1
Scanning step in the sample plane in the full area/ at 1:10 mode (nm)
0,08/0,008
Height range (μm)
1± 0,2
Vertical measurement step (nm)
<0,02
P r e s e t   p a r a m e t e r s :
    - tunnel gap voltage (V)
0 ±  2,3
    - tunnel current (pA)
60 ÷ 5000
Tunnel gap voltage setting (measurement) step (mV)
0,04
S i g n a l  p a r a m e t e r s  f o r  t h e  t u n n e l  g a p :
Signal form
Arbitrary;
it is preset programmatically
Frequency (kHz)
10 ÷ 100
3*3 nm frame scanning time at atomic resolution (s)
Up to 7
5*5 μm frame scanning time (min)
Up to 4
System operation mode setting time (min)
Up to 2
A C  v o l t a g e  s u p p l y :
- Voltage (V)
220
- Frequency (Hz)
50
Power consumption (W)
50
O p e r a t i o n  m o d e s :
    - constant current value scanning;
    - constant height value scanning;
    - measurement of surface current-voltage characteristic.

Examples of scans obtained with the help of «Umka» NTC

Island-like graphite film
 at gold surface,
5.12 х 5.12 μm
Film from TOKAMAK walls,
0.39 х 0.39 μm
Carbon nanotube
at he surface of graphite paper,
0.31 х 0.31 μm

We offer to see the gallery of other images obtained with the help of «Umka» NTC  (file of 1,1 Mb size).

MAIN ADVANTAGES

  • high reliability and plausibility of obtained results;
  • possibility of fulfilling studies in conventional atmosphere, at various temperature and pressure values;
  • non-destructive studies;
  • "in situ" obtaining scanning and measurement results;
  • ensuring «soft» (without «sticking») approach of needle (probe) to the surface of sample (at probability of 90% and more). It allows retaining the probe spike and prolongs its lifetime;
  • high scanning rate;
  • absence of mechanical elements demanding precise adjustment, tuning, lubrication and prophylactic maintenance;
  • high temperature stability allowing fulfilling long term manipulations with separate groups of atoms;
  • enhanced vibrostability, acoustic and electrical noise immunity;
  • low intrinsic noise level;
  • usage of «intellectual» algorithms of scanning and approaching the probe to the surface in the software;
  • modern software of open architectu;
  • does not require special training (fixing a sample and replacing a needle require the simplest laboratorian skills);
  • unpretentiousness (it can operate in usual rooms analogous to office ones (in auditoria, at exhibitions, etc.));
  • small dimensions.
As regards its technical characteristics, «UMKA» complex corresponds to the best STM represented at the world market but it is significantly easier to operate and cheaper. It creates real opportunities of mass usage of the complex in the spheres of science and training specialists as well as in many branches of the Russian industry for the purpose of their technological re-equipment meeting modern requirements of scientific and technical progress.

«UMKA» is awarded with:

  • Diploma of honour of the IIId Specialized Exhibition «NANOTECHNOLOGY AND NANOMATERIALS–NTMEX-2006». Moscow, the building of The Moscow Government, December 5 - 7, 2006.
  • Diploma and medal of the 8th Specialized Exhibition «Double Purpose Products and Technologies. Diversification of the Defense-Industrial Complex». Moscow, All-Russia Exhibition Center, October 2 - 5, 2007.
  • Diploma and medal of the 9th Specialized Exhibition «Double Purpose Products and Technologies. Diversification of the Defense-Industrial Complex». Moscow, All-Russia Exhibition Center, October 24 - 28, 2008.

APPLICATION AREAS

The complex can be used in the sphere of science and education for:
  • training students, post-graduate students and specialist of various specializations in the field of working at atomic-molecular level;
  • fulfilling fundamental and applied research works (including spheres of solids surface physics, material science, nanoelectronics, heterogeneous catalysis, space technologies, biology, etc.) at atomic-molecular level in scientific institutions and university laboratories;
  • fulfilling educational activity in the sphere of nanotechnologies among schoolchildren and various population layers.
Technical characteristic of scanning tunneling microscope, which is a part of «Umka» NTC, allow using it in various branches of real economy.
Using it in branches of industry should provide raising the level of quality control of manufactured products because «Umka» NTC allows fulfilling:
  • studying materials and surfaces of products by methods of tunneling microscopy and spectroscopy at atomic-molecular level;
  • works, which demand determination of characteristics of materials and media and their analysis (including analysis of condition of coatings and surfaces of treated details; studying electro conductive surfaces, initiation of corrosion; express analysis in criminalistic laboratories, etc.) at atomic-molecular level.
As regards medicine, biology and ecology, «Umka» NTC allows:
  • fulfilling studies of various biological objects (DNA and RNA molecules, parts of viruses and bacteria, sections of biological tissues: reuticazone, etc.) of dimension up to 5-6 μm;
  • fulfilling fine analysis at atomic-molecular level in laboratories (in particular, it opens new opportunities in diagnostics of diseases and in protection of health of people and animals).

USERS

«UMKA» NTC PRICE-QUALITY-CONVENIENCE RATIO and USAGE SIMPLICITY are favorable for users. It is competitive at internal as well as at international markets.
Up to date about 100 scientific organizations, universities and scientific and production enterprises, including Russian Scientific Center «Kurchatov Institute», M.V.Keldysh Center, Central Scientific Research Institute for Machine-Building Technology, Institute of Biological Instrument Engineering of the Russian Academy of Sciences, M.V.Lomonosov Moscow State University, Institute for Machine- and Instrument Making, Astrakhan, Saratov and other state universities in many regions of Russia have purchased «Umka-02-Е» NTC and «NANOskill» complex according to results of price quotation contests and open auctions.
Kuban State University has purchased 10 «Umka-02» complexes for training students of «Nanotechnology» specialization and for conducting research works in the field of analysis of structure of conductive and magnetic samples at atomic-molecular level. 5 «NANOskill» working place» complexes are purchased by N.E.Bauman Moscow State Technical University. Two «Umka-02» complexes are a part of equipment of «Nanotruck», which is the first «Nanotechnologies and Nanomaterials» mobile tutorial class in Russia. It has been created on demand of Moscow Committee on Science and Technologies for school education system.

KITTING

«Umka» NTC minimal delivery set includes:
  • piezomanipulator block with vibration isolation system;
  • control block;
  • control block software;
  • sets of test samples, materials, tools;
  • tutorial movie;
  • user's guide;
  • data sheet.
«NANOskill» working place complex includes:
  • «UMKA» NTC;
  • facility for sharpening probes;
  • personal computer (including LC monitor, keyboard, mouse and wires) with characteristics providing «Umka» NTC operation;
  •  methodic materials on preparing laboratory works on «Nanotechnologies» specialization (5 pcs).

ACCESSORIES:

  • tungsten probes (needles) for STM sharpened with electrochemical method;
  • methodic materials on preparing laboratory works on «Nanotechnologies» specialization;
  • sets of test samples for STM and for fulfilling laboratory works on nanotechnologies.

TRAINING

Engineering and Educational Center works at Concern "Nanoindustry". Basic skills and necessary practice of working with "Umka" NTC can be acquired there.
Representatives of interested organizations may get an opportunity of attending Engineering and Educational Center beforehand and being acquainted with equipment as well as estimating opportunities of "Umka" complex in solving specific problems at their own samples if necessary.
TECHNICAL SUPPORT.  We offer to send questions and remarks on "Umka" NTC operation via e-mail.
Please forward ORDERS ON DELIVERY "Umka" complex and accessories via e-mail.
 
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Updated 11.02.2011