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

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.