S.B. Krupanidhi

Professor Krupanidhi’s research on multi-component ferroelectric oxides has focused on the oriented and epitaxial growth by pulsed laser ablation, sol-gel processing and magnetron sputtering. He was the first to couple the ECR plasma to physical vapor growth for low temperature epitaxy in complex oxides. Professor Krupanidhi was one of the first to integrate ferroelectric thin films on semiconductors to demonstrate ferroelectric field effect transistors which subsequently became the backbone of the development of ferroelectric random-access memories (FRAMs). Based upon his significant contributions, he also functioned as a consultant to NEC, and Matsushita in Japan and Samsung in South Korea. Currently he is focusing on the development of engineered ferroelectric nano structures for accomplishing high capacitance density for ultra-high-density memories. The critical zones in the phase diagram of the PZT compositions for enhanced pyroelectric response considering both compositional and strain fluctuations in the microscopic regions were identified for the first time. Most recently these results are further confirmed by polarization mapping via piezo force microscopy by his group.

His group was the first to design and formulate the multilayered relaxers with higher orders of strain via electrostriction. Most recently, his group discovered an unconventional phase transformation in the asymmetrically multilayered relaxers through interfacial strain coupling. This is considered most important result for high density charge pumping through field and strain induced phase switching. The mechanical stain acts as a mediator among the electric and magnetic domains and their micro structural interactions among the domains. This aspect has been exploited in the artificially structured superlattices of the multiferroic perovskites. 

In the area of III-V compound semiconductors, Professor Krupanidhi developed space quality solar cells involving MOCVD growth of epitaxial GaAs on Ge substrates. Efficiencies of upto 19% were achieved and were authenticated by NASA. Besides the device development, his group pioneered the basic science of III-V epitaxy, p- and n- type GaAs growth using auto carbon doping, and banc gap narrowing phenomena in hetero epitaxy. In addition, his research work included successful development of solar cells based upon CIGS (CuInGaSe) and eliminating the toxic CdS layer. 

Most recently Professor Krupanidhi’s research has been extended to the design and development of quantum well and quantum dot structures of epitaxial III-V compounds, specifically for longer wavelength Quantum Well structured Infrared Photodetectors (QWIPs). First set of results already established the successful development of IR detectors which are operating in the wavelength ranges of 3-5 and 8-10 micron. His group also pioneered droplet epitaxy of quantum dots of III-Nitrides using MBE process. These quantum dots are successfully employed in the band gap engineering and tuning of wavelength in high bright LEDs.

Recent Publications: