Laboratory – Pan Research Group

Our laboratory is equipped with a wide variety of equipment for characterizing ferroelectrics, battery materials, catalysts, and metals.

Electron Microscopes

The electron microscopy instrucments at UCI are housed within the Center for Transmission Electron Microscopy (CTEM) in the Irvine Materials Research Insitute (IMRI). Members of our group are expert S/TEM users and work closely with staff members to run advanced experiments. For a full description of these facilities, visit https://imri.uci.edu/

JEOL JEM-ARM300F ‘Grand ARM’

The Grand ARM is the newly introduced JEOL 60-300 kV TEM, which offers 63 pm resolution at 300 kV for atom-by-atom characterization and chemical mapping. The wide pole piece gap (>6 mm) of the JEM-ARM300FC makes it possible to develop customized holders for a variety of in-situ TEM experiments to study the structure, properties, and dynamic behavior of nanostructured materials under applied fields, stress, and reactive environments. The Grand ARM is integrated with a new generation direct electron detection system (the Gatan K2 IS) and the newly released OneView cameras for optimum CCD imaging. The K2 IS is the most powerful camera available for TEM imaging, a game changer for electron microscopy, that enables the study of atomic scale details of structural changes dynamically within TEM (up to 1600 fps). This microscope is also equipped with an electron biprism for holography, double 100 mm² X-ray detectors for energy-dispersive spectroscopy (EDS) and the Gatan 965 GIF Quantum ER imaging filter with dual energy range EELS (DualEELS), suitable for the rapid mapping of elements with atomic resolution.

Nion UltraSTEM200 HERMES

Nion HERMES 200 has the highest spatial and energy resolution of any commercially available STEM, with many critical features not found on any other instrument. The unique design of the monochromator of the HERMES system provides an energy resolution for electron energy loss spectra (EELS) of 5.7 meV when operated at 60 kV and 4.2 meV when operated at 30 kV, with a long-term energy stability of the order of 10 meV/min. This allows vibrational spectroscopy to be carried out in combination with the spatial resolution and flexibility of the TEM. Thus, this unique microscope can explore physical phenomena such as lattice vibrational modes (phonon) and chemical-bond vibrations that are spatially highly localized. The Nion HERMES enables researchers to explore the atomic structure, chemical bonding, and local electronic structure of materials with the highest spatial and energy resolution in combination with ultrahigh energy resolution for EELS.

JEOL JEM-2800 S/TEM

This versatile 100-200 kV Schottky field emission TEM will serve as a workhorse for structural/chemical analysis of materials. It features high resolution imaging in TEM, STEM, HAADF, ABF, and secondary electron (SE) modes (analytical high-resolution pole piece), ultrasensitive elemental mapping with large angle EDS (dual dry solid-state 100mm² detectors), and the Gatan OneView IS camera for imaging and in-situ observations at 320 fps. Several of our in-situ holders are compatible with the 2800, including the Protochips Fusion select and Dens Solutions liquid cell holders. The 2800 was also recently upgraded with precession electron diffraction capabilities.

JEOL JEM-2100F Cryo-TEM

This 80-200 kV TEM is equipped with a field emission gun, a cryo cooling stage, a cryo transfer stage, and a Gatan CCD camera (OneView) and a K3 camera for the study of biological specimen at room and liquid nitrogen temperatures. The cryo TEM is suitable for observation of frozen hydrated specimens such as single proteins or two-dimensional crystals of membrane proteins. IMRI is equiped with all the necessary sample preparation tools for cryo-TEM experiments. The 2100 is also compatible with various liquid-cell in-situ TEM holders as well. In the study of hard materials, the 2100 is used for checking BF/DF imaging, diffraction, and checking sample quality.

Tescan GAIA3 SEM-FIB

The GAIA-3 XMH FIB-SEM is TESCAN’s newest, highest-end flagship dualbeam instrument. It has a unique three-lens electron optical design capable of dedicated modes for extreme high-resolution imaging (magnetic immersion mode), enhanced depth of focus, undistorted ultra-low magnification imaging, and live 3D stereo imaging. The instrument is fully equipped with beam deceleration, in-beam SE and BE detectors, retractable STEM and YAG BE detectors, off-axis Everhart-Thornley SE detector, SITD secondary ion detector, 5-reservoir gas injection system (W, Pt, SiO_x, H₂O, XeF₂), in-situ plasma cleaner, electron beam lithography package, autoslicer, 3D Tomography Advanced package, electron beam induced current (EBIC) system, Oxford AZtecEnergy Advanced EDS Microanalysis System with the latest X-Max 150 mm² silicon drift detector, Oxford AZtecHKL Advanced NordlysMax2 integrated EBSD System, and Omniprobe 400 port-mounted piezo nanomanipulator, the last of which provides an ideal tool for the preparation of TEM specimens for structural imaging and chemical analysis with atomic resolution in combination with the state-of-the-art TEMs described above. The smart chamber design of the GAIA XMH FIB-SEM instrument allows for the simultaneous milling and collection of EBSD patterns without the need to move the sample. This flexibility is unique to TESCAN and will provide best-in-class accuracy and throughput for EBSD and EDS.The 3D-EDS and EBSD reconstructions are critical for understanding the structure and chemistry of materials.

TEM Holders

Our group has several specialized TEM holders for performing more advanced experiments. Our capabilities include in-situ heating, biasing, and cooling, and imaging in gas or liquid environments. We also have holders to perform tomography. Below is a complete list of our available holders:

Protochips Atmosphere TEM Environmental Gas Cell – Allows samples to be imaged under a gas environment, up to 1 atmosphere pressure. Upgraded with a mass spectrometer and the AXON system.
Protochips Fusion Select – Enables in-situ biasing or heating of samples attached on MEMS chips
Protochips Poseidon Select Liquid Cell – Allows samples to be imaged in a liquid environment
Hummingbird Scientific TEM Nano-Manipulator – A probe holder that allows samples to be pushed a manipulated in-situ
Hummingbird Scientific Single-tilt Tomography Holder – A single tilt capable of ultra high tilt angles for collecting tilt series data
Nanofactory Instruments Scanning Probe Holder – A probe holder that is also capable of scanning probe measurements in-situ
Mel-Build High Angle Triple Axis (HATA) Holder – A tomography holder that can be tilted precisely along all three axes. Specialized for combining diffraction experiments with tomography

Film Growth and Characterization

Pascal Oxide Pulsed Laser Deposition (PLD) System

The Pascal system employs powerful turbo pumps and uses only metal vacuum seals and gaskets throughout the vacuum chamber, so that the ultimate base vacuum pressure is 5×10^-9 Torr. The combinatorial mask positioning unit enables the fabrication of integrated nano-structured chips and molecular-layer composition-spread library on a single substrate simultaneously and automatically. With the precise movement of the mask board patterned with rectangles or triangles at close position of substrate during thin film deposition, composition gradient thin film patterns can be formed on one piece of substrate, speeding up the development process and reducing cost at once by rapid and effective screening. The Pascal system employs a unique laser heater that can generate substrate temperatures greater than 1000 °C, where the heat is produced by a focused, fiber coupled laser. This technology is more powerful and more energy efficient than traditional metal alloy filament, and also very robust in long term use. The system can load 6 targets at one time, enabling multilayer hetero-epitaxial thin film growth in a single experiment. A load-lock transfer component is included for easy exchange of targets and substrates, also keeping the UHV in the main chamber at all times for continuous depositions.

NT-MDT NTEGRA Spectra Scanning Probe Microscope

Prof. Pan’s Research Laboratory is equipped with a state-of-the-art NTEGRA Spectra scanning probe microscope (SPM) combined with Raman mapping as well as scanning optical imaging from NT-MDT Inc. The system is fully capable of atomic force microscopy and electronic measurements including piezoresponse force microscopy (PFM), conductivity measurements using scanning spreading resistance microscopy (SSRM), Kelvin probe microscopy (KFM), and capacitance mapping. It is also capable of scanning tunneling microscopy in air, and of scanning near-field optical microscopy with appropriate tips. An additional low-noise amplifier allows input voltages up to +/- 50 volts, allowing electronic measurements of low conductivity samples. In addition to the AFM and STM techniques, the system is coupled with a high resolution confocal Raman spectrometer, allowing simultaneous collection of Raman spectra coincident with scanning probe measurements. It is currently equipped with a 532 nm DPSS laser, with a proven point resolution of ~460 nm. As AFM/STM and Raman can be aligned coincidentally, it is possible to use tip enhanced methods to achieve sub-wavelength Raman resolution as in tip-enhanced Raman scattering (TERS), giving simultaneous chemical, electronic, and surface structure at the nanoscale. Spectra are recorded by a low-noise Andor CCD camera, where the CCD is thermoelectrically cooled to -60 C during imaging. The combination of optical and scanning probe techniques is a powerful tool to map the effects of microstructure and variations in material chemistry on electronic and photovoltaic properties. The photocurrent under irradiation by several different wavelengths, three can be simultaneously equipped in the spectrometer, can be directly measured and correlated with surface or cross-sectional structures. In addition, the effect of slight chemical variations is apparent in Raman. The combination of these measurement techniques allows direct access to microstructural, chemical, and electronic properties that are essential in designing high efficiency photovoltaic materials.