The linearly graded two-dimensional p-n junction

We study the potential distribution, depletion length, and capacitance-voltage characteristics of two-dimensional (2D) linearly graded p-n junctions. It is shown that the total-depletion length is proportional to the square root of the contact potential difference, in contrast to the linear dependence for an abrupt 2D junction. The junction capacitance varies logarithmically with the applied voltage. A graph of capacitance as a function of logarithm of voltage drop across the depletion layer should be a straight line, whose slope indicates the abruptness of a 2D p-n junction. (C) 2004 American Institute of Physics.