Surface Charge Effects in Ballistic T-Branch Nanojunctions

We analyze the influence of the surface charge on the operation of ballistic T-branch junctions based on InAlAs/InGaAs layers by means of a semi-classical 2-D Monte Carlo simulator. For this sake we propose a new self-consistent model in which the local value of the surface charge is dynamically adjusted depending on the surrounding carrier density. We will show that the TBJ rectifying behavior, that is the down-bending shape of the output voltage V_C as a function of the applied voltage, V_R= -V_L=V, is found to be much influenced by the surface charge. A satisfactory agreement is achieved between simulated results and experimental measurements.