We present an idea of a two-dimensional p-n-junction formed as a contact between two regions of a thin, quantumsize film with different types of conductivity. Here we report on the results of calculations of the potential distribution and the barrier potential under thermal equilibrium. We also determine the width of the surface charge (depletion) layer, which has a linear dependence of the build-in and applied voltages between the contacts. The specific capacitance of a two-dimensional p-n-junction practically does not depend on the applied voltage and is determined by the dielectric constant of the surrounding medium. We have compared the results of Shottky depletion approximation with the exact calculations. The results show that in spite of the weak screening capability of two-dimensional electrons, the use of the depletion approximation for description of various properties of two-dimensional p-n-junctions (for example, for the calculation of current-voltage characteristic) is justified.
Физика и техника полупроводников, 2002, том 36, вып.