There has been tremendous growth in the semiconductor industry in the last few decades. This has largely followed Gordon Moore’s prediction in the 1960s that number of transistors per chip would double every two years approximately. However, there have been concerns about scaling limits of silicon MOSFETs during the last twenty years [1]. As a consequence, variations of the basic theme have been suggested and two categories have emerged, one of which attempts further miniaturization while the other aims at diversification. © 2020, Springer Nature Switzerland AG.