Physics Research,Laboratory IIT Patna
1. Langmuir-Blodgett Trough
This setup is used to study thin films formed at air-water interface. Various organic/ inorganic systems with amphiphilic functional groups can be studied. This is an excellent model system to study thermodynamics of 2D system. Surface manometry experiments and deposition of film onto solid support (LB film) can be carried out. This is also equipped with a surface potential measurement unit which can sense the dipole orientation of the floating monolayer. Overall , this is a technique which allows precise control on the molecular assembly and is very useful for molecular nanoarchitectonics.
2. Brewster Angle Microscope
This microscope enables insitu observation of floating monolayers at air-water interface. At Brewster’s angle, there is no reflection of the incident laser light from the surface of clean water. But with a monolayer floating on it, there will be some reflection which is enough to build an image in a CCD camera. The intensity of the reflection is related to the thickness and refractive index of the floating monolayer.
3. Physical vapour deposition system
This system is equipped with thermal evaporation and electron-beam evaporation system. Thin films of various metals and organic/inorganic materials can be deposited. Using proper masks, one can design and fabricate device structures.
4. Semiconductor Parameter Analyzer
Used for device characterizations by current-voltage and capacitance-voltage measurements. In addition, designer pulsing system enables us to identify advanced properties of a device.
5. Basic Scanning probe microscopy setup
This setup has atomic force microscopy and scanning tunneling microscopy. In atomic force microscopy, the available modes are contact, non-contact and current sensing. In addition to topography imaging, one can use this setup for single point measurements such as current-voltage (I-V) spectroscopy and force-distance (F-D) measurements. This allows us to extract nanoscale electrical and mechanical properties of thin films.
6. Advanced scanning probe microscopy setup
This setup is equipped with the following:
- Standard AFM modes of contact, tapping, current and phase contrast imaging.
- Standard STM mode.
- Current-Voltage measurements with various current ranges.
- Mechanical property measurements with a precise control of the forces suitable for very soft materials as well as the standard organic thin films.
- Scanning capacitance measurements allow to investigate the defect state densities at metal/insulator interfaces. This is particularly useful for device characterisations like transistors with high k-dielectric gate insulators.
- Variable temperature dependence measurements.
- Nanoscale electrochemistry using liquid cell STM.
In addition, advanced measurements can be carried out by interfacing external electronics like waveform generator, current amplifier, lock-in-amplifier and Giga Hertz oscilloscope.
7. Manual probe station with temperature controller
This setup is equipped with 2 probes , micropositioners and an optical microscope. This is useful for taking current-voltage, capacitance-voltage and other electrical measurements on devices with micron order contact pads. This needs to be connected with external electronics such as source meters /semiconductor parameter analyzer etc. This setup will be upgraded to 4 probes soon. In addition, it has a temperature controller which can vary the temperature of the sample stage below and above the room temperature.
8. Spin coater for thin film preparation
This is a facile technique for preparing thin films on a substrate from solutions. Both static dispense and dynamic dispense methods can be employed as per need. A wide range of rotations per minute (rpm) is accessible enabling thickness control of the films.
9. Ultra Sonicator
This is routinely used for substrate cleaning and sample preparation. Different ranges of frequency with varying timer setting is available. Low frequency is used for regular cleaning and high frequency is used for deep cleaning. For sample preparation, one can use it for exfoliation of nanomaterials in solutions.
These instruments are supported by IIT-Patna , DST-SERB, DST-FIST program.
