Figure 2.

Carrier mobility and mobility devices. (a) Schematic of a typical device with the nanowire positioned on top of a substrate with an oxide layer, which acts as a global backgate. Current through the nanowire flows from the source to the drain contacts, where the source-drain spacing constitutes the channel length. (b) Pinch-off curves, i.e., current as a function of backgate voltage, V_BG, and a fixed source-drain (bias) voltage obtained from devices as described in panel (a), where the channel length is specified accordingly. Inset with a top-view SEM image of a representative device.¹⁰⁶ (c) Average mobility in InAs and InSb quantum wells and nanowires, which are calculated based on mobility values from various publications: InAs quantum wells^107−112, InAs nanowires^{85,98,113,114}, InSb quantum wells^15,115−118, and InSb nanowires^58,119−121. All averages are based on low-temperature mobility measurements. (d) SEM images top-view (left) and 35^o-tilted (right) of a nanowire device with Hall contacts to extract nanowire mobility from Hall measurements. Reprinted with permission from ref (122). Copyright 2012 AIP Publishing.