This applet is to help students develop the ability to make a direct and immediate association between the Fermi level position or the temperature and the distribution of electrons among energy states. Figure 1 shows a snap shot of this applet at a particular Fermi level and temperature. Figure 1 The Fermi distribution applet. As the user changes temperature using the horizontal scroll bar at the bottom of the applet, the electron distribution among the energy states adjusts to the new temperature. The pedagogic value of this applet is that students get to observe directly and visually the meaning of Fermi level and temperature in the Fermi distribution of electrons.
Students are able to change the semiconductor material among a few different selections.
Figure 2 shows an instance of this applet. The applet for Fermi level in the band gap and carrier concentration. The Fermi level position in the band gap plays a critical role in controlling the electronic property and the device characteristics of a semiconductor. However, using the traditional educational media such as static illustrations, equations, and lecture, it is often difficult to provide the students with ability to make an immediate association of the position of Fermi level with the carrier concentrations, and vice versa. The band diagram of a PN junction diode is the building block or the starting point of band diagrams for a more complicated device structure such as a bipolar junction transistor.