Contact Information

Email:  lodha@ecn.purdue.edu

Phone: 765-494-3494

 

Personal Webpage

http://min.ecn.purdue.edu/~lodha

 

Academics and Research

Doctoral student (Aug. 2001-present), ECE Dept., Purdue University. Advisor- Prof. David B. Janes Project- Currently working on two and three terminal device structures using thin, bulk-like molecular layers. Molecules using nitro and/or amino groups are being studied. The project invloves characterization (ellipsometry, UV/IR spectroscopy, STM imaging) of thermally evaporated molecular layers and electrical characterization (I-V, dI/dV, I-T measurements) of the device structures.  Organic thin film transistor structures utilizing molecules such as pentacene and napthacene will also be studied. Masters in ECE (Aug. 1999-Dec. 2001), ECE Dept., Purdue University. Advisor- Prof. David B. Janes

Thesis- Experimental and modeling studies of Schottky contacts to low-temeprature-grown GaAs

This work is a study of Fermi level pinning in Schottky contacts on MBE grown n-GaAs, with and without an as-grown intrinsic or a Be-doped-LTG:GaAs surface layer. Ex-situ, non-alloyed Schottky contacts were fabricated using Ni, Ti and Mg for short air exposure times. High frequency C-V measurements and Poisson simulations incorporating a complete description of the defect states in the LTG:GaAs interface layer were used to extract the interface barrier height. The results indicate that unlike n-GaAs, the Fermi level is highly unpinned for metal-LTG:GaAs interfaces because of a significant "extrinsic" reduction in interface state density. I-V and I-T measurements were used to verify the accuracy of the C-V technique.

Publications:

1) S. Lodha, D. B. Janes, and N.-P. Chen, "Fermi level unpinning in ex-situ Schottky contacts on n-GaAs capped with low-temperature-grown GaAs," Appl. Phys. Lett., (to appear).

2) S. Lodha, D. B. Janes, N.-P. Chen, and E. H. Chen, "Unpinned interface Fermi level in Schottky contacts to n-GaAs capped with low-temperature-grown GaAs; experiments and modeling using defect state distributions," J. Vac. Sci. Technol. B, (submitted).

This work has also been presented at the 43rd  Electronic Materials Conference (Notre Dame, June 2001) and at the 29th Conference on the Physics and Chemistry of Semiconductor Interfaces (Santa Fe, Jan. 2002).

 

Bachelor of Technology, (May 1995-Aug. 1999), EE Dept., Indian Institute of Technology, Bombay, India. Advisor- Prof. Juzer Vasi Thesis- Radiation and reverse bias stressing damage in Si-SiGe HBTs and Si BJTs Publications: 1) A. Topkar, S. Lodha, et al., "Ionizing radiation induced degradation of SiGe HBTs," Proceedings of the 10th Intl. Workshop on Physics ofSemiconductor Devices, pp. 659-662, New Delhi, 1999.