Interfaces between crystalline Si and amorphous B: Interfacial interactions and charge barriers

The recently found crystalline silicon-amorphous boron (c-Si/a-B) heterojunction has been successfully applied in the detection of short-wave UV photons. These detectors play a decisive role in the progress of nanoelectronics fabrication. The c-Si/a-B heterojunction could not be explained using the existing 'instrumentarium' in semiconductor physics. We investigated the c-Si/a-B interfaces using ab initio molecular dynamics simulations. The simulations reveal atomic ordering of the a-B atoms adjacent to both the Si{0 0 1} and Si{1 1 1} substrates. Charge transfer occurs from the interfacial Si to B, thereby forming Si+/B- charge barriers, which induce an electric field in the nearby regions. The obtained information here is helpful in furthering our understanding of the physics behind the c-Si/a-B junctions, as well as driving the development of a new 'instrumentatrium' in solid state physics.