Cool a PN Junction  - LED Band Gap


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 Code Number :   7A30.10

Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

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Condition :   Good  
Principle :   Photoelectric Effect   
Area of Study :  Modern Physics  
Equipment :   Identical LED's with wires, 3 volt battery, liquid nitrogen, 300 ml Dewar.

Procedure :   Plug in two LED's and show that they have the same visible frequency or color.  Dip one of the LED's into liquid nitrogen until it is as cold as possible.  Remove and place beside the other LED.  Visible color change should be apparent.
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   References

John W. Jewett, "Get The LED Out", TPT, Vol. 29, # 8, Nov. 1991, p. 530.

 

Jurgen W. Precker, Marcilio A. da Silva, "Experimental Estimation of the Band Gap in silicon and Germanium from the Temperature-Voltage Curve of Diode Thermometers," AJP, 70, (11), Nov. 2002, p. 1150.

A. Sconza, G. Torzo, G. Viola, "Experiment on the Physics of the PN Junction," AJP, 62, (1), Jan. 1994, p. 66.

J. A. Davis and M. W. Mueller, "Temperature Dependence of the Emission from Red and Green Light Emitting Diodes", AJP, Vol. 45, # 8, Aug. 1977, p. 770.

John B. Kwasnoski, "A Laboratory Investigation of Light-Emitting Diodes", AJP, Vol. 40, # 4, Apr. 1972, p. 588.

 

Charles Day, "Light-Emitting Diodes Reach the Far Ultraviolet,"  Physics Today, July 2006, p. 15. 

Noble M. Johnson, Arto V. Numikko, and Steven P. DenBaars, "Blue Diode Lasers," Physics Today, October 2000, pp. 31-36.

 

Charles Kittel, Introduction to Solid State Physics 5th Edition, John Wiley & Sons, Inc.

"Photonic-Crystal Advances," How it Works - Science Supplement, Spring 2000, pp. 319.

T. D. Rossing, C. J. Chiaverina, "#6.8, Light-Emitting Diodes", Light Science, Physics and Visual Arts, p. 140.

 

Mail Questions and Comments to:  Dale Stille