Estimate of substrate influence on space-charge-limited current

The Mott and Gurney law, which expresses the space-charge-limited current in intrinsic material, cannot be used for planar structures. An I/V curve is plotted for a quasi-intrinsic material. For a doped substrate, the I/V curve is simply displaced by ¿V. In a planar structure, the s.c.l.c. between two n layers, across the p¿ substrate, can be lowered by biasing the substrate.