.
Category
- Spectroscopy and Spectrometry » X-Ray Photoelectron Spectroscopy
Booking Details
UPS
Facility Management Team and Location
csubbu@chem.iitb.ac.in
912225767194
Prof. Amartya Mukhopadhyay
Prof. Manoj Neergat
Prof. Saurabh Vijaykumar Lodha
Prof. Rohit Srivastava
Prof. Debabrata Maiti
Prof. Smrutiranjan Parida
Prof. Dinesh Kabra
Prof. R Murugavel
Prof. Shaibal K. Sarkar
Prof. Sankara Sarma
V. Tatiparti
Prof. Ashutosh Gandhi
Prof. Arindam Sarkar
Facility Features, Working Principle and Specifications
Working Principle:
Electron spectroscopy for chemical analysis (ESCA) instrument comprises of X-ray photoelectron spectroscopy (XPS), Ultra-violet photoelectron spectroscopy (UPS) and Auger electron spectroscopy (AES) / Scanning Auger Microscopy (SAM).
The surface to be analyzed is placed in a vacuum environment and then irradiated with photons (X-ray or Ultra-violet). The incident photons release electrons (called photoelectrons) from their electronic structure (core-levels and valence band) and ionize the atoms. The kinetic energy and the number of photoelectrons are precisely measured and counted respectively using an analyzer -detector based on which the binding energy and the intensity of the photoelectron are determined. AES/SAM is based on the Auger effect (series of internal relaxation events upon ionization of core level) leading to emission of electrons called Auger electrons. It uses primary electron beam (3 to 10 keV) and the possibility to focus and scan this primary electron beam in nm and µm range. The Auger electrons are part of the secondary electron spectrum with characteristic energy allowing one to identify the emitting element. The experimental setup is somewhat similar to that of SEM with a difference, that is, the electrons are not only used for imaging but also for chemical identification of the surface atoms.
Limitations: ESCA can detect all the elements except H and He. The detection limit is 0.1%
Reference Books:
- An Introduction to Surface Analysis by XPS & AES, John F. Watts & John Wolstenholme, Wiley 2003.
- Surface Analysis – The Principle Techniques, Edited by John Vickerman & Ian Gilmore, Wiley 2009.
Instructions for Registration, Sample Preparation, User Instructions and Precautionary Measures
- Internal users can register online.
- External users need to down load registration form., the samples could be sent along with authority letter, filled form, and online completed payment details. Also mention if samples are hazardous or non-hazardous. Sample size required is 3 mm x 3 mm thickness less than 3 mm. By post if sample damages we will not be responsible. After receiving samples along with above mentioned documents, results will sent in 5-7 working days, through email mentioned in form.
- Getting Back the samples: Users desiring to get back the samples need to mark on the form. Collect them from the lab between 9:30 AM to 11:00 AM after two-three days of receipt of results through email (for sample collection no separate email will be sent) and uncollected samples will be disposed off after ten days of the completion of the work and no reminders will be sent.
- Maximum size of samples should be 5 mm x 5 mm x 5 mm. Smaller samples of the size 3 mm x 3 mm or 3 mm diameter are more suitable. For samples of different sizes, the user is required to contact the ESCA laboratory staff.
- Label the samples only on the sample containers. Sample labels/codes shall be of three letters/number.
- ESCA analysis is surface sensitive. Do not contaminate the surface of your samples by any means; including touching them with or without gloves to be analysed
- The sample should be completely dry and it should be stable in ultra-high vacuum (no out-gassing allowed).
- Powders should be made into pellets or from a thin coating on a clean conducting substrate like silicon, aluminium or copper foil. Pressing powder in to indium foil is also another method .User should clearly mention if the sample needs etching (surface cleaning) before recording the data. It may be noted that the etching may alter the chemical composition and chemical state to some extent; which needs to be taken into account when interpreting the data.
- Samples containing organic molecules / polymers and some high vapour pressure elements such as Na, K, S, P, Zn, Se, As, I, Te or Hg are not suitable for depth profile analysis.
- UPS and Auger is possible only on sufficiently conducting samples. Insulating samples in the form of very thin films on the conducting substrate may work.
- Registered user will be allotted time as per queue.
- User should submit the samples to the ESCA lab between 9:30 AM and 11:00 AM on the scheduled day.
- Samples will be loaded in to the system on the submitted day and analysis will be carried out after 4 to 6 hours or on the next day. Data will be sent through email.
Charges for Analytical Services in Different Categories
The following charges* are applicable for External Users:
Description | Academic | National R & D Lab | Industry/Non- Govt. Agency |
XPS analysis Per sample | Rs. 3350/- | Rs. 6000/- | Rs.12000/- |
UPS analysis per sample | Rs. 3350/- | Rs. 9000/- | Rs. 12000/- |
XPS + UPS analysis per sample | Rs. 6700 | Rs. 14000/- | Rs. 24000/- |
Depth profile analysis per sample | Rs. 3700/- | Rs. 15000 per hr + 6000 per additional hr | Rs. 30000 per hr +12000 per additional hr |
Applications
- Chemical states of elements
- Relative quantification of each chemical state of each element
- Thickness of thin films
- Depth profiling
- Spatial distribution of material and chemical state
- Elemental composition of surface and quantification of their relative concentration
Sample Details
SOP, Lab Policies and Other Details
Publications
1) Dharmveer Yadav, Rahul Kumar Das, Sumit Saxena, Shobha Shukla, “OGF nanocomposite foam for enhanced recyclability and oil-recovery”, Journal of Cleaner Probuction, 137266, (2023).
2) Karthik Kiran Sarigamala, Alexander Struck, Shobha Shukla, Sumit Saxena, “Heterophase interfacial hybrid//grapheme nanoscrolls based high performance lithium-ion hybrid supercapacitor”, Electrochimica Acta, Volume 450, 142266, (2023).
3) Abhishek Pandey, Rahul Kumar Das, Amit K. Chakarborty, Shobha Shukala, Sumit Saxena, “Nanodefects assisted removal of reative dyes using biomass derived reduced 3D-OGFs”, Journal of cleaner production, volume 362, 132257, 15August (2022).
4) Ramu Banavath, Anand Abhinav, Rohit Srivastava, Parag Bhargava, “ Highly sensitive ascorbic acid sensors from EDTA chelation derived nickel hexacyanoferrate/grapheme nanocomposites/grapheme nanocomposites”, electrochimica acta, volume 419, 140335, 1 july (2022).
5) Mihir Kumar Jha, Neelam Sunariwal, Bradyn J. Parker, Neil Cameron, Chandramouli Subramaniam, “Multi-cationic ionic liquid combination enabling 86- fold enhancement in frequency response and superior energy density in all solid state supercapacitors, Journal of energy storage, Volume 53, 105164, September (2022).