R,oorn- t em per at ure quantum-const riction rectifier
Roman Sordan · 1997
Abstmct- A simple quaritum structure is proposed which is predicted to operate as a reliable rectifier at room temperatures. This diodc for the nanostructures is a qiraiitum wire with an asymmetric quantum coustrict,ion (AQC) which works in the coherent transport regirrie. We find that an AQC structure acts like a Schottky barrier if the constriction gradually widens between two parts of a quaiitum wire. Such device geometry creates an asymmetric barricx which could enable the forward currents three orders of magnitude higher than the reverse currents, at T = 300K. The current-voltage characteristics of the proposed rectifier have regions of negat~ive differential resistance (NDR) and multiple peaks. Structurally imperfect mesoscopic diodcs retain rectifying features, although t,he actual 1 - V characteristics are different in comparison to the pcrfect devices. 1. ~NTRODIJCTION Advance of' the nanolechnologies enables fabrication of subiiticronieler-scale (iiiesoscopic) devices, arid thus stimulates research in the field of the physics of the low-dimensional structures. The minia.turiza,tion of' integrated circuits and components approaches nearly atomic-scale dimensions. Therefore there is a need for developing new basic electronic comporicnts for na,iioelectronics, witah the device physics bnscd 011 the qiranturn mechanic,s. For example, a 'Lsliaped waveguideiicture is proposed as a. possible way for cxploiting quaiitum interference eff'ect, for realizing device fimclions such as switching or a.inplification [I] or analogt,o-digitiil conversion [2], Alt,ernative diode structures have been also proposed, based on advanced fabrication techniques. Allyii, Gossard arid Wiegmxnri [3] have suggest,cd a uiiipolar semicoriductor rectification structure, werP t,he potcntial ba,rricr, basic part, of a.ny diode, is crea.t.ed by modulating the mole fraction of A1 irr a niolecular Iieani epitaxy (MBE) grown Al,Gal-,As/Gahs heterostructure. Further research on tlie asymmetric qumtuin barriers, produces new ideas such as single indented barrier [4] or wide-narrow (WN) junction [5]. We have found that, for mesoscopic structures; a simple diode could consist of only two identical quant,irm wires of different, widths (Wide and Narrow) [.,I.