Dr Kotnala obtained his Ph.D on Silicon Solar Cell from Indian Institute of Technology, IIT Delhi in 1982 and was the first PhD on Solar Cell in India. Dr Kotnala has got long experience in the research of solar cell to develop low cost fabrication technology. A process of fabrication of P ^± NN ⁺ silicon solar cells by simultaneous diffusion of boron and phosphorus into N-type silicon through a thermally grown silicon dioxide layer of 0.1 micron thickness was the main Ph.D. work. The process is well suited for large scale production of back surface field (BSF) silicon solar cell. Moreover, this work was published in “ASSET” United National University publication as “Low Cost Process – Solar Cell”. To enhance the efficiency of solar cell some new initiatives were undertaken in his work.

His remarkable contribution in Solar Cell is very important and distinct as he published a book on it in 1986 which is popular even today. The book authored by Dr. R. K. Kotnala and N.P. Singh entitled “Essentials of Solar Cell” was the first book on solar cell in India. This book on solar cell was first book in India 1986, written when research in solar cell was just initiated. It inspired & helped many young students to pursue work in this area. The testimony to the book’s importance and popularity may be gauged from its inception as text book recommendation in B. Arch all over India by Deptt. Of Architecture for last 4 years and also it is being used widely by researchers in the field. Many research papers published on solar cells.

In 2012, 100 KW solar cell panels were planned & erected at EQDC Gandhinagar in the capacity of Governing Body member of EQDC.

Dr Kotnala’s enriched experience in Solar Cell bestowed him as a Chairman, Project Monitoring Committee on the progress of BHEL mega project of Rs 54.33 Crores on PERC Solar Cell Technology from Ministry of New & Renewable Energy on March 2 & Aug 14, 2020.