| dc.description.abstract |
The investigation of tunneling of particles through potential barriers in semiconductor quantum wells has recently attracted much attention. Special focus is laid on resonant tunneling structures because of its importance in the field of nanoscience and technology and its potential applications in very high speed functionality devices and circuits. Among the numerous nanoelectronic devices proposed and demonstrated, the III-V based RTD is perhaps the most promising candidate for digital circuit applications due to its negative differential resistance (NDR) characteristic, structural simplicity, inherent high speed, flexible design freedom, relative ease of fabrication and versatile circuit functionality. There is a good practical reason to believe that these RTDs may be the next device based on quantum confined heterostructures to make the transition from the world of research into practical application. In this work, we have worked with two materials GaAs and GaN which are most useful for building next generation quantum devices. Apart from studying the tunneling as an electrical phenomenon, we have investigated how light of different energies affect the tunneling process in the two compound semiconductor materials chosen. Tunneling Current variation with different energies of barriers, barrier heights and electron energies has been studied. Eigen states have been found for the barriers. The effect of bias across tunneling has been reported. Precise control of tunneling using gate control (RTT) or Base control (for bipolar device) is presented with an optical control. The change in refractive index of a semiconductor on interaction with photon is exploited to derive the relation between the band gap of a semiconductor and incident light. A Bandgap variation ultimately leads to re-alignment of quantum states hence impacting the tunneling mechanism. |
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