Photogating in Suspended InAs Nanowire Field Effect Transistors for Neuromorphic Applications

Suspended indium arsenide (InAs) nanowires offer a unique platform for studying surface-driven transport phenomena due to their high surface-to-volume ratio and the absence of dielectric interfaces. In this work, we investigate the role of surface states in InAs nanowire field-effect transistors. Electrical characterization reveals a high electron mobility of ≈1500 cm2V−1s−1, alongside a subthreshold swing of 1.49 V dec−1, indicating a reduced gate efficiency caused by surface traps. Temperature-dependent analysis yields activation energies of ∼100 meV, confirming the dominant influence of shallow trap states on both threshold voltage and subthreshold slope. Under pulsed optical excitation, the devices exhibit persistent negative photoconductivity and gate-tunable hysteresis. The on/off current ratio exceeds 105 at 200 K. These effects are attributed to a photogating mechanism controlled by the interplay between gate voltage and photoinduced trap occupation. The demonstrated ability to modulate long and short-term memory behavior through optical and electrical stimuli highlights the potential of these nanowire devices for neuromorphic applications.