Observation of Degenerate One-Dimensional Sub-Bands in Cylindrical InAs Nanowires

Abstract

One-dimensional (1D) sub-bands in cylindrical InAs nanowires (NWs) are electrically mapped as a function of NW diameter in the range of 15-35 nm. At low temperatures, stepwise current increases with the gate voltage are clearly observed and attributed to the electron transport through individual 1D sub-bands. The 2-fold degeneracy in certain sub-band energies predicted by simulation due to structural symmetry is experimentally observed for the first time. The experimentally obtained sub-band energies match the simulated results, shedding light on both the energies of the sub-bands as well as the number of sub-bands populated per given gate voltage and diameter. This work serves to provide better insight into the electrical transport behavior of 1D semiconductors.

Magnetotransport Subband Spectroscopy in InAs Nanowires

“…These values are similar to those already reported on similar InAs NW devices [8]. Assuming independent scattering events between the 1D channels and a negligible contact resistance checked by four-probes measurements (not shown here), we deduce the electronic mean free path l 1(2) ≈ 140(90)nm for the first (second) subband, confirming the quasi-ballistic regime.…”

“…Despite tremendous effort, backscattering on defects is enhanced for the narrowest wires, concealing the 1D electronic properties [6,7]. Only recently, the first signatures of quasi-1D subbands in InAs NWs have been observed as steps in the conductance [8]. However, an exhaustive direct spectroscopy of the confined states in individual NWs remains unachieved.…”

One-Dimensional Quantum Confinement Effect Modulated Thermoelectric Properties in InAs Nanowires

“…2b presents a comparison between our experimental G(V g ) data at 40K and numerically calculated curves for 1D subband occupation number N 1D SUBBANDS vs. V g following Ref. 21. 34 The two fold degeneracy for subbands index higher than one was also included in the calculated N 1D SUBBANDS .…”

InAs Nanowire Devices with Strong Gate Tunability: Fundamental Electron Transport Properties and Application Prospects: A Review

“…What is more interesting is that below 100 K, the curve develops some step-like features. These stepwise conductance increases are explained as due to the population of 1D subbands [20,102] , in analogy to the behavior in quasi-ballistic InAs NW FETs discussed in section 2.2., except that here the conductance is much less than 2e 2 /h and we have diffusive transport. Fig.…”