About KP Technology

Prof. Iain D. Baikie is the CEO and founder of KP Technology. He began developing Kelvin Probes for surface analysis in the early 1980’s and has over 25 years experience with development and applications. Prof. Baikie is the inventor of the Off-Null, Height Regulated (ONHR) Kelvin Probe system. Prof. Baikie has held tenure’s at Universities and Research Institutes in Europe and USA and has previously been Chairman of a UK University Physics Group. He has published extensively in the fields of surface science and materials research and has pioneered introduction of modern educational tools in Physics Education. KP Technology was founded with the aim of bringing to the market new surface research tools that would allow specialists to investigate surface phenomena, provide equipment pathways for non-specialists and lastly to educate scientists, engineers and technologists in the capabilities of these emerging technologies. Since inception in 2000 KP Technology has experienced rapid growth and now services over 100 companies and research institutes worldwide in their materials research and characterization requirements. Our Scottish-based team consists of electronic and software engineers, materials research associates, training, sales and administrative staff. KP Technology has been awarded the SMART Award for Technological development and was the recipient of the SCDI HIE 2006 Research and Development award. Our customer references are exceedingly good and customer feedback allows us to continually improve our product features. We offer a spectrum of dedicated Kelvin Probe systems specially developed for applications in a variety of environments ranging from ambient, controlled atmosphere, relative humidity through to ultrahigh vacuum. No other company offers our range of products or equipment expertise. Our systems are available for sales and lease and we have several short term evaluation systems available to bona-fide educational institutes. KP Technology also performs a significant amount of material research and training consultancy, mostly based upon the work function or surface potential evaluation of client samples. References for this client service are easily found on the internet and include university, research institutes and national laboratories.

The Kelvin Probe

The Kelvin Probe is a non-contact, non-destructive vibrating capacitor device used to measure the work function (wf) of conducting materials or surface potential (sp) of semiconductor or insulating surfaces. The wf of a surface is typically defined by the topmost 1-3 layers of atoms or molecules, so the Kelvin Probe is one of the most sensitive surface analysis techniques available. KP Technology Systems offer very high wf resolution of 1-3 meV, currently the highest achieved by any commercial device. The Kelvin Probe does not actually touch the surface; rather an electrical contact is made to another part of the sample or sample holder. The probe tip is typically 0.2 – 2.0 mm away from the sample and it measures the ‘traditional work function’, i.e. that found in literature tables. Other techniques, using very sharp tips some 10’s of nanometers away from the sample, measure very reduced and distorted work functions due to the close separation of tip and sample. The physical form of a Kelvin Probe is a head unit containing a voice coil driving system and integral amplifier suspended above a sample. The vibrating tip and the sample forms a capacitor, having ideal, or parallel-plate, geometry. As the tip vibrates electric charge is pushed around the external detection circuit. By careful control of the tip potential and automatic capture and analysis of the resulting waveform both the potential across the capacitor and the capacitor spacing can be calculated to very high resolution. In scanning form the tip is steered across the sample surface using a high resolution 3-axis translator. The spatial resolution of the tip is approximately the tip diameter, we typically use tips of 2 and 0.05 mm as standard tips in air and anything from a sharp tip to 10 mm diameter in Ultrahigh Vacuum. The resulting 3D surface work function images contain information about surface structures, surface composition, thin films, defects, etc. In time-varying mode artifacts such as oxidation (corrosion), defect relaxation, etc can be observed. For semiconductor surfaces, both organic (Polymer) and inorganic (Si, Ge, CdS, etc) the Kelvin Probe is the only way to directly measure the Fermi-level. Changes in fermi-level, caused by illumination with white or monochromatic light, results in energy band shifts which can be used to characterize interface and bulk defect states. These techniques are termed Surface Photovoltage (SPV) and Surface Photovoltage Spectroscopy (SPS) for which KP Technology can supply both software and accessories for our systems. The Traditional Kelvin Probe actually produces the work function difference between the tip and sample. The kelvin method was first postulated by the renowned scottish scientist Lord Kelvin, in 1861. Typically the tip is calibrated against a reference surface, such as gold first. However KP Technology is the only company to offer absolute Kelvin Probes, which combine the Kelvin method and Einstein Photoelectric effect to produce absolute work function values (in eV).

The Kelvin Probe is a non-contact, non-destructive vibrating capacitor device used to measure the work function (wf) of conducting materials or surface potential (sp) of semiconductor or insulating surfaces. The wf of a surface is typically defined by the topmost 1-3 layers of atoms or molecules, so the Kelvin Probe is one of the most sensitive surface analysis techniques available. KP Technology Systems offer very high wf resolution of 1-3 meV, currently the highest achieved by any commercial device. The Kelvin Probe does not actually touch the surface; rather an electrical contact is made to another part of the sample or sample holder. The probe tip is typically 0.2 – 2.0 mm away from the sample and it measures the ‘traditional work function’, i.e. that found in literature tables. Other techniques, using very sharp tips some 10’s of nanometers away from the sample, measure very reduced and distorted work functions due to the close separation of tip and sample. The physical form of a Kelvin Probe is a head unit containing a voice coil driving system and integral amplifier suspended above a sample. The vibrating tip and the sample forms a capacitor, having ideal, or parallel-plate, geometry. As the tip vibrates electric charge is pushed around the external detection circuit. By careful control of the tip potential and automatic capture and analysis of the resulting waveform both the potential across the capacitor and the capacitor spacing can be calculated to very high resolution. In scanning form the tip is steered across the sample surface using a high resolution 3-axis translator. The spatial resolution of the tip is approximately the tip diameter, we typically use tips of 2 and 0.05 mm as standard tips in air and anything from a sharp tip to 10 mm diameter in Ultrahigh Vacuum. The resulting 3D surface work function images contain information about surface structures, surface composition, thin films, defects, etc. In time-varying mode artifacts such as oxidation (corrosion), defect relaxation, etc can be observed. For semiconductor surfaces, both organic (Polymer) and inorganic (Si, Ge, CdS, etc) the Kelvin Probe is the only way to directly measure the Fermi-level. Changes in fermi-level, caused by illumination with white or monochromatic light, results in energy band shifts which can be used to characterize interface and bulk defect states. These techniques are termed Surface Photovoltage (SPV) and Surface Photovoltage Spectroscopy (SPS) for which KP Technology can supply both software and accessories for our systems. The Traditional Kelvin Probe actually produces the work function difference between the tip and sample. The kelvin method was first postulated by the renowned scottish scientist Lord Kelvin, in 1861. Typically the tip is calibrated against a reference surface, such as gold first. However KP Technology is the only company to offer absolute Kelvin Probes, which combine the Kelvin method and Einstein Photoelectric effect to produce absolute work function values (in eV).

The Work Function

When a group of atoms or molecules are brought together to form a solid the highest occupied energy level, or fermi-level is termed the work function. The work function is continuous across the interior of the solid, however at the surface the electron energy is influenced by the exact state of the surface, e.g. type orientation and direction of the outer atoms and molecules. Thus different crystallographic orientations of the same solid may have different work functions. The work function of a surface can be modified by adsorbed layers, for instance in corrosion or oxidation of an iron surface, or by modification of composition or controlled contamination as in the case of polymer or inorganic semiconductors. When two or more materials are brought together the Fermi-levels equalize by a flow of electrons from the lower work function to the high. Detecting these electrons is in essence the way all Kelvin Probe systems work. The work function is often described in introductory textbooks as ‘the energy required to remove an electron from a surface atom to infinity or equivalently the vacuum level’. Although this description appears easy, in surface analysis one has to ask further questions such as which type of electron, where is it taken from and where does it end up? For example as an electron is removed a short distance ‘d’ from a conducting solid there is a so-called attractive image force (due to an imaginary positive charge a distance ‘d’ inside the solid). The force on the electron diminishes as ‘d’ gets larger and by approximately 30-50 nm it is exceedingly small. However some work function detection systems actually operate within this region thus the electron is not removed to infinity. This effect, coupled with the local electric fields in the vicinity of the tip, distort the work function data recorded. In all KP Technology systems the Kelvin Probe tip always operates at sufficiently large distances to produce the ‘True Work Function’ and further the mean spacing of the tip electrode above the sample is tightly controlled producing high-stability, repeatable measurements and allowing automatic system set-up.

The Baikie System

KP Technology systems are based upon unique features developed by Prof. Baikie, we are currently in our 6th Generation of design, with features unsurpassed by any other company:

• Highest work function/surface potential resolution • Off null and height regulation features invented by Prof. Baikie • Full digital control of all Kelvin Probe parameter • High signal levels, patented signal processing • Excellent system stability and repeatability • Very high rejection of driver talkover noise compared with piezoelectric

systems • World’s first commercial absolute Kelvin Probe system • Quick change probe tip allowing user selectable spatial resolution • Versatile equipment upgrade paths • Our Signal-to-Noise (S/N) features remain unsurpassed in the field • No expensive lock-in amplifier (LIA) is required

Lord Kelvin

William Thomson was born in Belfast in 1824, son of a mathematics professor he was educated in Scotland at the University of Glasgow, entering at the tender young age of 10 years. He graduated from Cambridge University in 1845. Thomson spent a year working with Pierre and Marie Curie and Henri Bequerel in Paris before leaving to set up the Worlds’ first dedicated Physics Laboratory at Glasgow University in 1846. Thomson was knighted in 1886 for his impressive contributions to thermodynamics, electromagnetic theory and communication, including the first transatlantic cable link. In 1892 he received the title ‘Baron Kelvin of Largs’, the ‘Kelvin’ is a stream running through the Glasgow University Campus. Kelvin was an exceptional talent and Glasgow was a hot-bed of scientific development around the time he held tenure. Kelvin rose to become Rector of Glasgow University and it says a lot about the man that, upon retiring, he enrolled as a student at Glasgow University. Lord Kelvin died in 1907 and was buried next to Issac Newton in Westminster Abbey. He published some 661 papers, took out 70 patents and had more initials after his name that any other man in the British Commonwealth. By all accounts Kelvin was one of the most gifted scientists of his generation: a talented orator and was sufficiently confident of his experimental achievements to incorporate public demonstrations of his methods. Kelvin’s original ‘probe’ consisted of two large discs of Copper and Zinc (which have clean work functions of 4.6 and 4.7 eV respectively) mounted on insulating shafts. He did not vibrate this arrangement (as we do now) but brought the disk either closer together or further apart to demonstrate charge flow using a gold-leaf electroscope. Aside from his academic endeavors Kelvin would have today been recognized as a serial entrepreneur: developing a wide range of equipment and techniques in his own commercial laboratory. He is thus a role model for KP Technology and indeed scientists, engineers and educators worldwide. KP Technology has supplied ambient and ultrahigh vacuum Kelvin Probe systems to both the Physics and Chemistry departments at Glasgow University and 3 systems to the Nanotechnology Department at the University of Ulster, Belfast, Lord Kelvin's birthplace. Prof. Baikie has also had the honor on several occasions of lecturing to postgraduate science students at Glasgow University, in Kelvin’s old Department.

Single Point Kelvin Probe (non Scanning)

Ambient Kelvin Probe System Package (KPSP, non Scanning) This entry-level Kelvin Probe system is easy to set-up; it is designed to give drift free measurements and rejects stray capacitance effects that plague other designs. Rapid System Set-up, Tutorials and Tip calibration included. Everything the investigator needs is included!

• Ambient probe head unit with integral amplifier • Standard Tip 2 mm diameter (50 µm diameter option) • Optical Grade Base, System Mounts with 25.4 mm Manual Translator • Dedicated Dell PC with Software and Data Acquisition System pre-installed • Vertical Probe Mount as Standard • Spare Tip, Cables, Manual, Getting Started Tutorials • Work Function resolution of 1-3 meV with Standard Tip • Sample Holder with Gold Reference Sample • Faraday Shield • Export of Data to Excel Compatible Spreadsheets • Options include Surface Photovoltage Package, Humidity Chamber, Spare tip, gold-coated Tips, (X,Y,Z) manual translator, etc • Transparent Upgrade option to SKP, SKP5050

Scanning Kelvin Probe

Ambient Advanced Scanning Kelvin Probe System Package (SKP5050) The SKP5050 system is our best-selling Kelvin Probe system, this is the configuration we use in-house for client samples. It is based upon the ASKP system but includes highly recommended options including color camera/TFT monitor, 2mm and 50µm tips, external digital oscilloscope, extended warranty.

• 2mm and 50µm tips • Work Function resolution of 1-3 meV (2mm tip), 5-10 meV (50µm) tip • Tip to Sample Height Regulation to within 400 nm • 3D maps of surface potential and sample topography • Scan Probe or scan sample options • Color Camera, Zoom Lens, Dedicated TFT Display and optical mounts • Reference Sample with associated SKP topography • Spare Tip Amplifier • 24 months warranty

Ambient Scanning Kelvin Probe System (ASKP) The KP Technology Scanning Kelvin Probe comes complete with 3 axis micro-translator and controller permitting scanning measurements. The resulting 3D images are stunning! The feature list is identical to the Kelvin Probe System Package above, with the additional features:

• Sample Translation of 50 x 50 mm (2" x 2") • Tip Height Regulation 25 mm (1") • Translation Step 400 nm • Software Allows Real-time 3D reporting of WF and Height • Custom (X,Y) scan programming

UHV Kelvin Probe

Ultra High Vacuum Kelvin Probe System (UHVKP) This package comes with dedicated UHV Head Unit; Specifications are similar to the Ambient KP package

• Work Function resolution of 1-3 meV • Standard DN40 70 mm OD (23/4 inch) Mounting Flange • Flange Adapters for DN63 CF, DN100 CF (41/

2, 6 inch) • Stainless Steel Tip Sizes, typically 2-10 mm diameter • Tip to Sample Spacing Regulation • 100% UHV Compatible to 2 x 10-11 mBar • Manual Translation 50 or 100 mm • Custom Insertion Length • Ideal, Plane Parallel Vibration, 90O to the sample plane • Software Selectable Tip or Sample Biasing • Tip Preamplifier

UHV Kelvin Probe Options/Upgrades

• UHV Scanning Kelvin Probe 44 mm travel DN100 CF • UHV Scanning Kelvin Probe 20 mm travel, DN64 CF • Upgrade to Absolute Kelvin Probe (PhotoEmission Package) • Upgrade to Surface Photovoltage • Variable Tip Geometries • 25 mm Motorized Translation • Gold Coated Tips • Additional Stainless Steel Tips • Test Sample Mounted as Standard

Services

KP Technology performs a significant amount of material research and training consultancy, mostly based upon the work function or surface potential evaluation of client samples. References for this client service are easily found on the internet and include university, research institutes and national laboratories. Consultancy Using our state-of-the-art Kelvin Probes KP Technology offers a highly accurate materials analysis service. Analysis can be carried out on a broad range of material types including semi-conductors, solar cells and bio-technology surfaces. We are continually researching analysis techniques to accommodate new types of samples, increased sample sizes and to provide analysis under varying environmental conditions. KP Technology Training Courses 1. KP Probe Tutorial and ‘Hands-on’ Workshop A 2-day course aimed at explaining the Kelvin method to beginners. Covers Surface Work Function, Fermi-Level Equilibrium, Good Kelvin Probe Design, Signal Characterisation, Tip Biasing Procedures, Measurement Optimisation, Sample Interpretation, Practical Training on in-house Systems, Experimental Design. Examples of metals, semiconductors and polymers are considered. 2. Surface Characterisation Workshop A 2-day course aimed at Surface Characterisation in the High Vacuum-Ultrahigh Vacuum environment. Both the Kelvin method and complementary techniques are discussed. Standard work function and surface potential systems are considered, together with interpretation of work function changes. Semiconductor surfaces are treated in some detail along with surface photovoltage measurements. Good Experimental Design and Practical Training on in house systems.

Application Area'sThe fields of application of our probes are constantly expanding, current known applications include: • Adsorption • Battery-systems • Biology • Biotechnology • Catalysis • Charge Analysis • Coatings • Corrosion • Deposition • Dipole Layer Formation • Display Technology • Education • Emission • Fermi-level Mapping • Fuel Cells • Ionisation • Medical Devices • MEMS • Metals • Microelectronics • Nanotechnology • OLEDS • Phase Transitions • Photosensitive Dyes • Photovoltage Spectroscopy • Polymer Semiconductors • Pyroelectricity • Semiconductors • Sensors • Skin • Solar Cells • Stress • Surface Contamination • Surface Chemistry • Surface Photovoltage • Surface Potential • Surface Physics • Thin Films • Vacuum Research • Work Function Engineering

*denotes multiple system purchases

Adsorption University of Sao Paulo

Biotechnology

Porex Inc Harvard University

Marine Biological Laboratory National Research Council*

Okayama University Purdue University

Charge

Massachusetts Institute of Technology (MIT)

University of Glasgow*

Corrosion European Space Agency (ESA)

Ford Motor Company Inc Helsinki Technical University

J. Heyrovsky Institute Sheffield University

Tata Steel University of Alberta* University of Hawaii

University of Manchester University of Oxford*

Deposition

SAES Getters University of Heidleberg

Wright Patterson AFB

Display Toshiba

Electrodes

Burle Electro-Optics Inc University of Mainz

Emission

University of Cincinnati

Fuel Cells Israel Institute of Technology (Technion)

HardDisk Seagate Inc

Materials Indian Institute of Technology

(New Delhi)

MEMS Bosch GmbH

Royal Holloway University

Metals Atomic Energy Commission (CEA)

Atomic Weapons Establishment Johnson Matthey

Los Alamos National Laboratory* United Kingdom Atomic Energy Authority

Nanotechnology

University of Ulster*

NEA Devices University of Virginia

OLEDS

American Materials Inc Cambridge Display Technology

Institute of New Materials Jilin University

Karlstad University National Changhua University

National Institute for Materials Science National Institute of Advanced Science

OLED-T Ltd Osram OptoSemiconductors Inc

Plextronics Inc South Bank University

Toyko Institute of Technology University of California, Berkley

Photovoltage

University of Delft

Semiconductor University of Munich

University of South Florida Frontier Semiconductor

Sensor

Honeywell International Space Electronics

Solar Energy First Solar Inc

Nankai University Solyndra Inc

Stress University of California Los Angeles

Thin Film

Techscience Bestec GmbH

Centre for Process Innovation Dupont*

Hunan University Intex Inc

Iowa State University Kovio Inc

North Dakota State University Plastic Logic

Saint Gobain NRDC Stanford University

Thomas Jefferson National Accelerator Fac. Tokyo University

Graz University of Technology University of Latvia University of York

University Zaarbruchen Walter Schottky Institute

Vacuum

National Autonomous University of Mexico University of Bundeswehr

University of California Santa Barbara University of New Mexico

Siemens GmbH Specs Scientific Inc

Other

Ames National Laboratory National Physical Laboratory

Clients (by application)

Client References"I have been working the KP Technology Kelvin Probe and I have become quite comfortable with it. It is an excellent device and exquisitely sensitive." Prof. Andrew Ahn, Harvard Medical School, Harvard University, USA "I am still amazed at how much better the KP Technology probe performs compared with the other systems we've had in the lab, easily 20 times better." Dr. Roel van der Krol, Delft University, The Netherlands. "An excellent SKP system: we most appreciate your helpful support and explanations" Prof. D.J Wang, Department of Chemistry, Jilin University, China "The KP Technology SKP is a very reliable instrument. I have not had any problems since I got it in 2000. I am very satisfied with its performance." Prof. Dongyang Li, Department of Materials and Chemical Engineering, University of Alberta (dongyang@ualberta.ca) "The customer service is definitely very positive: responsive, courteous, and knowledgeable is how I would describe Iain and his company." Darin Laird, Senior Scientist and Materials Research Team Leader, Plextronics Inc, Pittsburgh, USA. "Everything has worked perfectly and I am very happy with the system" Prof. Marshall Porterfield, Purdue University, USA "The Kelvin Probe that you developed is wonderful because of the height regulation feature which other systems do not have. We have another company's Kelvin Probe: the KP Technology System is better in sensitivity, ease of use and customer service." Dr. Shinjiro Yagyu, National Institute for Materials Science, Ibaraki, Japan. "The KP Technology system was very attractive and very well packed. We have installed the Kelvin Probe successfully in the humidity chamber and it runs without any problem at all humidity levels. The signal is very stable." Dr. Antonius de Rooij, Head of Materials Mechanics and Processes Section, European Space Agency, The Netherlands.