Figure 2.

An illustration of how the pn junction is formed in a Si NW. a An SEM image of a NW indicating the p- and n-regions. b The expected phosphorus and boron profiles in the NW. The P profile was simulated by TRIM code, while the B profile was taken from the SIMS measurements of similarly doped Si layers. As can be seen, according to our process, the P and B profiles should cross in the middle of the NW resulting in a depletion region 40 nm long

Kanungo et al. Nanoscale Research Letters 2009 5:243-246   doi:10.1007/s11671-009-9472-x