In Situ TEM Biasing & Heating

Ferroelectric nanodomains evolution
at extreme temperatures.

The Lightning In Situ TEM Biasing & Heating Series provides you the power to obtain real-time information about your specimen under a controllable electrical and thermal environment. Investigate the next generation of nano-electronic materials and devices with the Lightning Series.

200kV/cm

Simultaneous Biasing

Resolution

800°C

Simultaneous Heating

Lightning Application Fields

Piezoelectrics

Electric field stimulus is the most efficient way to manipulate ferroelectric domains and temperature changes of ferroelectric devices limits its practical application. In situ TEM observation of the electric field induced domain evolution under a heating environment is important to improving the electromechanical properties of piezoelectrics.

ReRam

The current−voltage measurements and corresponding structural changes during resistive switching process of the potential ReRAM materials in real time is essential for improving the stability and scalability of the most promising next-generation nonvolatile memory devises.

Solar Cells

Research into photovoltaics has grown significantly in the past 10 years with three core areas of focus: (1) efficiency, (2) technology development and (3) material development. Papers already published using in situ TEM and the Lightning system shows that this application field is only growing in demand.

Simultaneous biasing & heating studies

Nano-scale investigations of nano-electronic devices & materials

E-field induced dynamics of piezoelectric nanoparticle

Experiment: Ba-Sr-Ti-Na-O3 at 800 °C and 210 kV/cm Researchers from TU Darmstadt using the Lightning D9+ JEOL system investigated led free piezoelectric material Ba-Sr-Ti-Na-O3 in the form of nano particles. The nano particles were sintered until a core shell structure formed and a high e-field applied to show domain changes. The in situ TEM video shows through the FFT that the core is ferroelectric and possess domains, however, the shell in paraelectric (non ferroelectric). Showing the superior performance of the Lightning system, high resolution was achieved while applying 210 kV/cm at 800 °C.

Domain evolution in ferroelectric materials

Ferroelectric materials are characterized by the existence of spontaneous electric polarizations at a temperature well below Curie temperature. In a small area, the polarizations may share a same direction and form the so-called ferroelectric domain. The spontaneous polarization can be reversed by applying an external electric field exceeding the coercive field. Investigating the ferroelectric properties at both temperature and external electric field is important for applications such as data storage and optical frequency converters. Here we present a recent experiment performed using the Lightning D9+ (double tilt with an 8 contact Nano-Chip), demonstrating the capability of delivering both high electric field and stable temperature. Simultaneous electric field and heating is also possible, however, not shown below. The material under investigation is BZT-0.5BCT, which has a Curie temperature around 90 °C and a coercive electric field of 2~4kV/cm.

In Situ TEM Analysis of Organic–Inorganic Metal-Halide Perovskite Solar Cells under Electrical Bias

Abstract Changes in the nanostructure of methylammonium lead iodide (MAPbI3) perovskite solar cells are assessed as a function of current–voltage stimulus by biasing thin samples in situ in a transmission electron microscope. Various degradation pathways are identified both in situ and ex situ, predominantly at the positively biased MAPbI3 interface. Iodide migrates into the positively biased charge transport layer and also volatilizes along with organic species, which triggers the nucleation of PbI2 nanoparticles and voids and hence decreases the cell performance.

Quentin Jeangros*†§, Martial Duchamp‡⊥, Jérémie Werner†, Maximilian Kruth‡, Rafal E. Dunin-Borkowski‡, Bjoern Niesen†, Christophe Ballif†, and Aïcha Hessler-Wyser† † Photovoltaics and Thin-Film Electronics Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Rue de la Maladière 71B, Neuchâtel CH-2000, Switzerland § Department of Physics, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland ‡ Ernst Ruska—Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich D-52425, Germany
nl-2016-03158b_0006

Sample preparation with conventional techniques

The sample preparation techniques used for preparing traditional TEM samples including lamellas, nanowires and particles are suitable for the Nano-Chip. FIB lamellas are the most commonly used sample for biasing experiments and DENSsolutions in conjunction with some close academic partners have developed a unique FIB workflow using a customised FIB stub specifically designed for the Nano-Chip. This process significantly reduces the total workflow time and makes the success in transfer much higher. Additional methods such as micro-manipulators are suitable for sample preparation onto the Nano-Chip.

Nano-Chip

Up to 8 contacts for simultaneous
biasing & heating

Based on the well established and industry leading MEMS based technology used in the Wildfire system, the Lightning system incorporates the 4-point-probe method in both biasing (4 contacts) and heating (4 contacts) on the single Nano-Chip. This allows for simultaneous biasing measurements at elevated temperature, with the micro-heater and temperature sensor surrounded by the biasing lines. The complete range of Nano-Chips are available to in situ researchers allowing for dedicated biasing or heating experiments or simultaneous experiments options.

200kV/cm at 800°C

RT – 1,300°C Dedicated

Ultimate in Stability

Sample Holder

Introducing the Nano-Chip to the microscope

The Sample Holder is the critical element connecting the Nano-Chip with the microscope and provides in situ researchers with the ability to measure pico amps and apply high voltages up to 100 volts, all within a heated environment. Made from titanium for its optimal mechanical stability, the double tilt Sample Holders provide in situ researchers with the largest application space.

Hardware & Software

Total control over the biasing & heating environment

For biasing experiments a source measuring unit (SMU) is required to precisely source voltage or current and simultaneously measure voltage and/or current. The majority of SMUs are compatible with the Lightning system and our preferred supplier is Keithley as they offer a wide range of SMUs suitable for all experiments. Controlling the SMU can be done via the device screen and Keithley Kickstart software. The heating function is managed through DENSsolutions’ Digiheater software and can be precisely controlled via the local temperature sensor and fast feedback-loop.

Some great work from our customers

Testimonials

“Continual advancements of in situ TEM by DENSsolutions provides an exciting and ever-improving level of detail into a range of nano-scale dynamic processes. In particular, the Lightning system allows us to simultaneously heat a FeRh system through magnetic transitions with extreme stability, whilst also applying electrical pulses so that we can drive and visualise magnetic domain wall motion with unparalleled control.”

Dr. Trevor Almeida

University of Glasgow

“The ability to apply high electric-fields and to simultaneously perform high-resolution experiments at elevated temperatures is frankly impressive! The new and exciting possibilities that the DENSsolutions Lighting series offers trailblazing new directions at the forefront of materials research.”

Dr. Leopold Molina-Luna

Technical University of Darmstadt

“In operando TEM observations provide a unique opportunity to visualise the correlations between the electrical properties and the structural changes. The exceptional stability of the DENSsolutions holder allows the in operando TEM experiments to be performed with atomic resolution. Recently, we successfully observed structural changes of resistive switching and organic-inorganic metal-halide perovskite solar cells devices while under electrical stimulus inside a TEM”

Dr. Martial Duchamp

Nanyang Technological University

Frequently Asked Questions

What is the size of sample recommended for biasing experiments?

The sample size depends on the type of experiment to be executed. For 4 point probe measurement approach, where all four biasing electrodes need to be bridged, the required sample length is 10-15 microns. In the situation where only two inner electrodes are involved in the experiment (for example, E-field application), the sample size is can be in the order of 4 microns.

What preparation methods other than FIB could be usable for biasing experiments?

FIB is very important in transferring materials for biasing experiments, especially for lamella’s as it’s the most commonly used method. While for 1D materials (e.g. nanowires) and 2D materials (graphene), the transfer method can vary dependent on what tools you have available such as a micro-manipulator.

What is the homogeneity of the electrical field?

There are several different designs for the Lightning range of Nano-Chips. In this example below, the one devices has three areas where samples can be loaded for electric field measurements.yjtjjjtjtyjtyAs the simulation above indicates, the electric field is highly uniform, as high as 99%  in the gap between the electrodes.

What TEM pole-pieces are compatible?

Due to the variety of pole-pieces available for both the JEOL and FEI microscopes, please see the brochure for confirmation. However, the Lightning series is compatible with the smallest pole-pieces found in the JEOL UHR (e.g. ARM) and the FEI Supertwin (e.g. Titan).

What really sets the 50V / 100V limit?

Two reasons:

  1. To avoid the electric failure between connection pins in the vacuum. (Electric sparks)
  2. To avoid breakdown of SiNx at high electric field (the limit is lower at elevated temperature).

Be aware, the specified voltage is not the breakdown voltage of our system, but in fact to ensure a low leakage current. Therefore, in reality one could go much higher than the specified numbers if the experimental details allow.

Can my sample survive the electrical loading induced?

Yes. For common samples, such as lamella’s, metallic nanowires, etc., these samples have proved to be safe during loading without any special care needed. As for sensitive semiconducting nanodevices, grounding connections through source measuring unit / power supply (e.g. Keithley) are needed to make sure there is no static voltage drop over nanodevices, therefore, preventing any damage of high current to the sample.

Download the Lightning brochure

For more information on workflow, applications and specifications.

Contact us

Feel free to contact us with any further questions.

Request a Demo or Quote

Request a quotation or demonstration at your lab.

Contact us

Feel free to contact us with any further questions.

Request a Demo or Quote

Request a quotation or demonstration at your lab.