This is a visually simple applet that shows the qualitative relationships among energy states, the Fermi function, and temperature, along with some excellent supplementary material. Users can interact with the material by changing the temperature and fermi level.
There is a problem at T=0. The author indicates this problem in his accompanying tutorial. The problem becomes much more evident if the temperature parameter is dragged through its range rather than stepped through its range using the up and down arrows located at the side of the temperature indicator.
Identify Major Learning Goals:
To understand impact of the Fermi-Dirac function and temperature on the occupancy of localized electron states in semiconductors.
Nature of the Fermi-Dirac distribution; simple electronic quantum states; basic Fermi-Dirac statistics.
Content Quality
Rating:
Strengths:
The variation of the Fermi-Dirac distribution with temperature is accurate and enlightening. The approach to the classical Boltzmann distribution as the temperature increases is one of the features that can be easily visualized by the student. The relationship between Fermi-Dirac statistics and occupancy of localized electron levels is demonstrated in a superior fashion. The supplementary material, e.g., mathematical analysis, references, worksheet, is excellent.
Concerns:
There is a self-admitted problem at T=0. One has to be careful how the temperature is changed.
Typically, the Fermi-Dirac distribution is plotted in a very static manner with different curves for different temperatures. Here the student can actively change the temperature and see how the distribution changes. The effect of this changing distribution on the occupancy of localized electron states is easily visualized and understood. This gives a good qualitative sense of the Fermi level and temperature effects on the occupation of energy states. The supplementary material is very good.
Concerns:
Use(s) Material is not Suited For: Quiz/Test (without substantial instructor-added material)
If the student is not careful how the temperature is varied, dragged rather than stepped, anomalous results can be obtained.
General Comments on Effectiveness: It is an effective teaching tool which is effective in helping the student understand quantum statistics, the effect on occupation of levels, and the transition into the regime of classical statistics. The supplementary material provides a clear mathematical analysis of the occupation of energy states and a worksheet for students to check their understanding. In addition,
the reference section gives links to many other sources of information that will be of interest to students seeking more information.
Ease of Use for Both Students and Faculty
Rating:
Strengths:
The steps required to alter the Fermi level and temperature were very straightforward but better results were obtained when the temperature was stepped. The tutorial was entirely self-contained with appropriate references and links.
Concerns:
None
General Comments on Usability: The applet is simple to use, and clearly presents the qualitative aspects of the material.
Creative Commons:
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