Engineering Sciences 154 
For reference  not applets: Two graphs of carrier concentration vs.electron energy: linear plot and logarithmic plot (see below)
Applet: A graphical illustration of the formation of a PN junction diode and its band diagram. It shows both the band diagram and a schematic crosssection of the device as the junction approaches its thermal equilibrium. See also the non applet: Energy Diagrams of ptype and ntype semiconductors 



Point to note: (see
Math. Analysis)











Applet: Space charge and electric field in biased PN junction.Note, in particular, how depletion layer stretches with increasing back bias. 



Applet: Biased PN Junction: band diagram, diffusion and drift currents, etc. It shows both the energy band under bias and the animated carriers flowing across the junction.Note, in particular, the importance of accounting for the recombination of carriers.See also the non applet: Energy diagrams of biased pn homojunctions 





Applet: Current flow in forwardbiased pn junction An applet that shows an animated flow of carriers in a simplified band model. 
