Controlled Pore Formation on Mesoporous Single Crystalline Silicon Nanowires: Threshold and Mechanisms

Figure 6

Example for nitrogen gas adsorption/desorption isotherms on an ensemble of nanowires of (a) highly (blue/green triangles) doped and (b) undoped (red/black) silicon. The isotherms of the highly doped substrate show a hysteresis which is characteristic for mesoporous surfaces on the nanowires. Silicon nanowires from undoped wafers show no pores. Inset (c): magnification of the low-pressure region of the adsorption isotherm of the undoped silicon nanowires to illustrate the formation of the first adsorbed nitrogen monolayer, indicated by the knee at .