MultiView 2000TS Integrated Atomic Force Microscopy (AFM) inbuilt with RAMAN
Dr. Pala’s research lab also has a MultiView 2000TS Atomic Force Microscopy (AFM) inbuilt with RAMAN spectroscopy and Near-field scanning optical microscopy (NSOM) (MultiView 2000TS) and it’s supporting accessories from NANOIONICS IMAGING LTD., USA. The model MultiView 2000TS AFM-RAMAN system is basically used for imaging by probe microscopy of a vast range of nanoscale materials (e.g. Carbon nanotube, Graphene, Boron Nitride, Silicon Nitride, Gallium Nitride transistors, ZnO & TiO2 Nanowires, Silicon and Silicon Nanowires etc.) along with RAMAN mapping which reveal the chemical features, bonding, phonon vibration of nanomaterials. Recently, in scientific field, research trend incorporated with developing of new materials associated with its real life applications as a form of different devices. Scanning Probe microscopy (AFM, STM, MFM) is one of the techniques which can goes down to atomic scale resolutions with precise imaging. Similarly, Raman spectroscopy and Near-field scanning optical microscopy is nondestructive characterization techniques which provide information regarding inter-atomic bondings characteristics and chemical structures & local stresses respectively. Therefore, this integrated system is highly useful for characterizing some special nanostructures like graphene nanoribbon, serpentine carbon nanotubes including inorganic as well as polymeric nanowires and nano-composites etc. In some special cases, like surface functionalized nanoparticles, it is highly difficult to characterize their topography as well as inherent bonding between nanomaterials and functional groups. In this context, researchers have to carry out all those characterizations in several distinguished systems with different resolutions which are basically unprolific and sometimes formulate fallacious conclusions. Furthermore, this integrated system is added advantage for investigating the characteristics of some complex systems like, bio-molecule functionalized nanotubes, metal/polymeric-quantum dots heterostructures and nano-channel conjugated with different DNA for biosensing applications.This instrument is a low cost for the academic institutions and research laboratories involved in nanoscience and nanotechnology research and can be used for wide range of functional and pristine materials characterizations at nano-scopic level. In sum, this specialized characterization system is much faster and dramatically easier in order to obtain conspicuous accurate results instead of other cumbersome technique.
The complete working system of MultiView 2000TS system includes all scanning probe microscopy (e.g AFM, STM, MFM, LFM etc)) along with Raman spectroscopy, tip enhanced raman spectroscopy and near-field scanning optical microscopy(As shown in Figure 1, left). This system includes complete Atomic Force microscope with aperture/aperture-less cantilever-based NSOM experiments, consisting of fully XY & Z scanners using flexure guided scan system for all three axes, SLD XE-NSOM head, top illumination module, high resolution digital CCD camera with digital zoom, bottom collection module, motorized Z stage, motorized focus stage, manual precision XY sample stage, control electronics, computer, software and accessories. Further, the system is inbuilt with 400-700 nm laser assembly, optical grating system and a high resolution digital CCD camera for precise signal detection.
The salient features of the requested instrument AX 5010 PE-CVD are:
- 400 to 700 nm Laser which provide the flexibility of wide range of materials characterizations.
- Excitation laser input is a single-mode fiber with collimator that includes an XYZ-align mechanism for the
optimal illumination and a linear polarizer (Extinction ratio: 100,000:1).
- Completely Decoupled XY & Z Scanners with Closed-Loop Feedback with
- Scan range X,Y :170 mm x 170 mm, Z: 12 mm
- Resolution: 1.5 nm (closed-loop), < 0.01 nm (open-loop)
- Z axis noise level: 0.02 nm (typical) / 0.05 nm (maximum)
- Top and bottom illumination mode for Raman spectroscopy, tip enhanced Raman spectroscopy and near field scanning optical microscopy.
- Transmission Detection Module includes:
- Collection wavelength range: 400 – 700 nm (visible light)
- Photon detector: Hamamatsu H8259-02 (185 – 900 nm)
- Includes optical components consisting of a rotary mirror, vision CCD, focus lens, manual XY stage for focus lens alignment, and PMT
- Side Reflection Module includes:
- Allowed wavelength of the illumination laser: 400 – 700 nm with integrated 20× objective lens and digital CCD detectors
- AFM supports standard for AFM/SPM modes including true non-contact mode, dynamic contact mode, contact mode, LFM (lateral force microscopy), F/D spectroscopy and performs STM, MFM, EFM, Enhanced EFM, DC-EFM(PFM), SKPM, SCM, SSRM, SThM, FMM, Conductive AFM, VECA, ULCA, Nanoindentation with upgraded version of the system software.
THz Time Domain Spectroscopy System (TDS)
Our time domain spectrometer (TDS) covers the spectrum from 0.1 THz up to 3 THz which gives us the capability of characterizing our devices in a broad THz spectrum. The optical set up is prepared to make transmission measurements. The system is also capable of making measurements at cryogenic temperatures. The modification in the optical set up will also let us to measure reflection from the devices if necessary.
A GaAs emitter antenna is excited with 20mW 100 fs pulsed laser at 780 nm wavelength. The emitted THz and probe laser is mixed inside the ZnTe crystal and polarization rotation is measured as a function of time (delay line). The terahertz pulses are generated by an 100fs ultrashort pulsed laser and last only a few picoseconds. A single pulse can contain frequency components covering the whole terahertz range from 0.05 to 3 THz. For detection, the electrical field of the terahertz pulse is sampled and digitized. In THz-TDS, the electrical field of the THz pulse interacts in the detector with a much-shorter laser pulse (0.1 picoseconds 20mW) in a way that produces an electrical signal that is proportional to the electric field of the THz pulse at the time the laser pulse gates the detector on. By repeating this procedure and varying the timing of the gating laser pulse, it is possible to scan the THz pulse and construct its electric field as a function of time. Subsequently, a Fourier transform is used to extract the frequency spectrum from the time-domain data.
Backward Wave Oscillator (BWO) Based THz Spectroscopy System
Dr. Pala’s Integrated Nanosystems Research Lab (INSYST) has also backward wave oscillator (BWO) based THz spectroscopy system from Microtech Instruments Inc. The spectrometer is flexible to measure transmission and reflection spectra in 0.1THz – 1.5 THz. The entire setup is computer controlled and through phase shift measurements can extract the real and imagery parts of the dielectric constant.
ETS Lindgreen Anechoic chamber with Rhode&Shwartz Spectrum Analyzer for antenna measurements
HP 8510C VectroNEtwork Analyzer
Internal Quantum Effciency measurement system
Janis Liquid He Cryostat