Influence of channel width on the performance of an injection-type ballistic rectifier: Carrier injection versus hot-electron thermopower

摘要

Injection-type ballistic rectification is achieved in an asymmetric Si/SiGe cross junction made from narrow channels, where the injectors are inclined with respect to the straight voltage stem. In this geometry an inertial-ballistic signal establishes due to the momentum direction of the injected electrons towards the lower part of the central voltage stem. Additionally, a diffusion hot-electron thermopower signal is superimposed which arises from an electron temperature gradient over a gate-confined region of the stem channel. We investigate the influence of the stem width on the rectifier performance. The inertial-ballistic signal disappears at a stem width larger than the 2D electron mean free path in contrast to the diffusion thermopower, which is independent of the stem width.