In my graduate work, I have worked on two different topics; 1) p type ZnO and 2) 2D materials. In my presentation, I will briefly discuss on p-doping problem in ZnO thin films and after that I will focus on 2D materials. The journey of 2D materials has started with graphene. Having zero band gaps in graphene shifted the attention of the community to inorganic layered di chalcogenides like MoS2, WS2, and ReS2 etc. These TMDs are three atomic thick and cationic planes are sandwich in-between two anionic planes. Due to having exciting electronic and valley properties, these TMDs are appropriate candidate for novel device applications. The main obstacle is large area epitaxial growth of these materials. In my work I will present how to solve these issues and their interesting optical properties due to their compressive strain . I will address how to control polly-type phase transition of these TMDs which is very much important for switchable device applications . Apart from these, I will discuss on optical properties of defects, 2D heterostrutures and layered specific band gap using high resolution EELS. 1. R. Sahu, D. Radhakrishnan, B. Vishal, D. S. Negi, A. Sil, C. Narayana, R. Datta, Substrate induced tuning of compressive strain and phonon modes in large area MoS2 and WS2 van der Waals epitaxial thin films, Journal of Crystal Growth, 470, 51-57 (2017). 2. R. Sahu, U. Bhat, N. M. Batra, H. Sharona, B. Vishal, S. Sarkar, S. Assa Aravindh, S. C. Peter, I. S Roqan, P. M. F. J. D. Costa, R. Datta, Nature of low dimensional structural modulations and relative phase stability in RexMo(W)1-xS2 transition metal dichalcogenide alloys, Journal of Applied Physics, 121, 105101 (2017) (Selected as Feature article and Front Cover page). 3. K. Dileep, R. Sahu, S. Sarkar, Sebastian. C. Peter, R. Datta, Layer specific optical band gap measurement at nanoscale in MoS2 and ReS2 van der Waals compounds by high resolution electron energy loss spectroscopy, Journal of Applied Physics, 119,114309 (2016). 4. U. Bhat, R. Singh, B. Vishal, A. Sharma, H. Sharona, R. Sahu, R. Datta, Distinct photoluminescence in multilayered van der Waals heterostructures of MoS2/WS2/ReS2 and BN, Submitted 2017.
Rajib Sahu is an integrated PhD student at JNCASR, Bangalore. He has completed his M.S in 2014 and submitted his PhD thesis on September 2017. His has worked on thin solid films, transmission electron microscope and density functional theory. His graduate work deals with growth of solid thin films (ZnO & 2D) and their characterizations using various experimental techniques.