Probing the Gate-Voltage-Dependent Surface Potential of Individual InAs Nanowires Using Random Telegraph Signals

We report a novel methocl for probing the gate-voltage dependence of the surface potential of individual semiconductor nanowires. The statistics of electronic occupation of a single defect on the surface of the nanowire, determined from a random telegraph signal, is used as a. measure for the local potential. The method, is demonstrated for the case of one or two switching defects in indium arsenide (InAs) nanowire field effect transistors at temperatures T = 25-77 K. Comparison with a self consistent model shows that surface potential variation is retarded In the conducting regime due to screening by surface states with density D(ss) approximate to 10(12) cm(-2) ev(-1). Temperature-dependent dynamics of, electron capture and emission producing the random telegraph signals are also analyzed, and multiphonon emission is identified as the process responsible for capture and emission of electrons from the surface traps. Two defects studied in detail had capture activation energies of E(B) approximate to 50 meV and E(B) approximate to 110 meV and cross sections of sigma(infinity) approximate to 3 x 10(-19) cm(2) and sigma(infinity) approximate to 2 x 10(-17) cm(2), respectively. A lattice relaxation energy of s (h) over bar omega = 187 +/- 15 meV was found for the first defect.