.This is regarding the numerical solving of the drift diffusion equations. In an online lecture (Dragica Vasileska (2006), "Drift-Diffusion Model, Part A: Introduction," https://nanohub.org/resources/1511.) it is mentioned that the mesh size should be smaller than Debye length for accurate results. Also , it is mentioned that for better convergence of solutions, lengths should be scaled with respect to the Debye length.
What is the significance of Debye length? What is the meaning of Debye length with respect to the semiconductors?
http://en.wikipedia.org/wiki/Debye_length#Debye_length_in_semiconductors
Mam trying to explain it in simple language for you
first of all note this simple definition
debye length :distance in semiconductor over which local electric field affects distribution of free charge carriers; decreases with increasing concentration of free charge carriers.
Now lets note
1) drift current is the result of gradient caused by electric voltages (gradient is difference of charge at two points)
2) diffusion current is proportional to gradient of concentration
Now take two oppositely doped semiconductor (P type and N type) at a certain distance parallelly you will find an electric field starting from one semi conductor slab and terminating at secondary slab this electric field affect the charge carrier concentration now this very length is deby length now if free charge carrier increases or distance between two slab increased to level where there is no effect of existing electric field on charge distribution then it shows the decrease in debye length
basicaly in simple language it is synonymous to field generated by magnet which affect the environment of its reach just the difference here in semiconductor it is between two oppositely charged semiconductor slab and the length of significant affect was invented by debye so debye length for further mam you refer here
http://www.physics.umd.edu/courses/Phys132/spring2014/LecturesA/Debye.pdf
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