Low-frequency electrical fluctuations in metal–nanowire–metal phototransistors

Abstract

Using low-frequency noise spectroscopy to explore the physical origins of electrical fluctuations in ZnO nanowire (NW) phototransistors featuring a metal-NW-metal configuration, we have found that bulk mobility scatterings gave rise to electrical fluctuations in the low-gate voltage (V G) regime, providing values of Hooge's constant in the ranges 6.0-9.6 × 10(-3) and 1.9-2.2 × 10(-1) in the dark and under UV excitation, respectively. When moving into the higher V G regime, we assign the electrical fluctuations to an interaction process involving trapping and detrapping of channel carriers by charge traps located near the NW-dielectric interface, suggesting that the mechanism of the electrical fluctuation transitioned from bulk NW-dominated to NW/dielectric interface-dominated regimes. We have also addressed the effective density of interface traps responsible for the electrical fluctuations in the high-V G region. This report provides physical insight into the origins of electrical fluctuations in NW phototransistors.

Ionic screening effect on low-frequency drain current fluctuations in liquid-gated nanowire FETs

“…Noise spectroscopy has been used widely as a sensitive tool for investigating the dielectric defect densities in FETs [29][30][31][32][33], the biologically binding events in nanosensors [34,35], and the origin of the scattering of transport carriers in nanoelectronics [36,37]. Therefore, we used it to explore the physical mechanism behind the low-frequency drain current noise characteristics of liquid-gated NW FETs under different ionic strengths in the above-threshold regime.…”

“…Therefore, we used it to explore the physical mechanism behind the low-frequency drain current noise characteristics of liquid-gated NW FETs under different ionic strengths in the above-threshold regime. The setup of the home-built noise measurement system used in this study has been described previously [33]. The inset to figure 2(b) reveals the low-frequency drain current noise power special density (S I ) for an NW FET operated at a value of V G of −1.2 V under the 0.1, 0.01, and 0.001 M pH-7 electrolyte buffers, showing typical f 1 b characteristics with a value of β of 1.4.…”