The idea of quantum computing was first explored in the 1970's and early 1980's by physicists and computer scientists like Charles GH. Bennett of the IBM Thomas J. Watson Research Center,  Paul A. Benioff of Argonne National Laboratory in Illinois, David Deutsch of the University of Oxford, and the late Richard P. Feynman of the California Institute of Technology (Caltech). This idea emerged as scientists were debating the fundamental limits of computation. They realized that if technology continued to go by Moore's Law, the continually shrinking size of circuitry packed onto silicon chips will get to a point where individual elements would be no larger than a few atoms. Then there was disagreement over the atomic scale the physical laws that rule the behavior and properties of the circuit are inherently quantum mechanical in nature, not classical. Then came the question of whether a new type of computer could be invented based on the principles of quantum physics. Quantum computing basics may be explored in depth here:-

Quantum Computing- Latest Technology