On the p-type character of Cd-and Zn-doped InAs nanowires

Abstract

InAs nanowires are potential materials for high speed nanoelectronic devicesdue to their high electron mobility among the semiconductor nanostructures.One of the main challenges, however, is to obtain a p-type InAs material, sincethe Fermi level is usually pinned at the conduction band, leading to an intrinsicn-type behaviour. Here we show through first principles calculations that InAsnanowires, doped with Cd or Zn substitutional impurities, can behave as p-typematerials. Differently from other III–V nanowires, these impurities introduce shallowacceptor levels. We show that the Zn impurity can be equally distributed along thenanowire radius, naturally compensating the surface levels. On the other hand,the Cd impurity is preferentially found in the core region, requiring a surfacetreatment to eliminate the surface pinning levels. These results explain the availableexperiments and show how and why p-type InAs nanowires can be obtained.