DIAMETER DEPENDENCE OF CURRENT-VOLTAGE CHARACTERISTICS OF ULTRASMALL AREA ALSB-INAS RESONANT-TUNNELING DIODES WITH DIAMETERS DOWN TO 20 NM

We have studied the current-voltage characteristics I(V) of ultrasmall area AlSb-InAs resonant tunneling diodes (RTDs) with diameters down t o 20 nm, Resonant tunneling peaks were observed for all the diodes at room temperature. The peak-to-valley ratio reduces with the decreasing diameter of the RTD, We found from the diameter dependence of the val ley current that the reduction is due to a contribution of the thermal ly activated surface current to the valley current. For RTDs with diam eters less than 100 nm, we observed fine structures around zero bias a t 4 K. They can be attributed to tunneling through zero-dimensional st ates confined by a RTD sidewall. (C) 1997 American Institute of Physic s.