Effect of field-focusing and ion selectivity on the extended space charge developed at the microchannel-nanochannel interface.

摘要: We present results demonstrating the effect of varying microchannel depth and bulk conductivity on space charge-mediated transition between classical, diffusion-limited current over-limiting in microchannel-nanochannel devices. The extended charge layer develops at depleted entrance when limiting is exceeded correlated with a distinctive maximum dc resistance. This shown to be affected by depth, via field-focusing, solution conductivity. In particular, we observe that upon their increase, becomes flatter shifts higher voltages.