JAVA Applets for Physical Electronics.

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JAVA Applets for Physical Electronics.

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Metal
Semiconductor
Metal
Semiconductor
Depletion Region
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Team Members

• Team Leader/Presentation
• Ramya Chandrasekaran
• Webmaster/Documentation
• Pujita Pinnamaneni

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Project Goal

• Design a JAVA Applet to help students understand
  the characteristics of Schottky diodes.
• Demonstrate the energy band gap and depletion
  width variations for varying concentrations and
  for different metals and semiconductors.
• Demonstrate how the free carrier concentration
  varies with temperature.

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Project Outline

• Review semiconductor physics of Schottky diodes.
• Develop simulation for band gap variation with
  respect to concentration for different metals and
  semiconductors.
• Develop simulation of n/ND and p/NA
  vs.temperature.

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Project Outline(cont.)

• Develop JAVA code to run these simulations.
• Design JAVA applets.
• Demonstrate the applets.
• Launch the Applets on the World Wide Web.

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Importance of JAVA Applets

• JAVA enables to develop user friendly
  applications.
• JAVA is the web language.
• Enables easy interaction .
• GUI concepts in JAVA accepts user inputs through
  mouse and keyboard and enables immediate
  feedback.
• Animations and interactive applications are
  possible.

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Importance of Schottky diodes

• The role of schottky diodes is firmly established
  in the semiconductor technology because they
  perform functions better than most of the other
  junction devices.
• These contacts are used in large number of
  devices such as FETs,BJTs,photo
  detectors,LEDs,Double Heterostructure lasers and
  Solar cells.
• Metal - Semiconductor junction are used for high
  speed rectification.

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Simulation of Schottky diodes.

• Schottky diodes are formed in two ways
• Metals deposited on n-type semiconductor.
• Metals deposited on p-type semiconductor.

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Schottky Contacts.

• In n-type Schottky contacts,electrons flow from
  the conduction band states in the semiconductor
  to the metal because they have higher energy
  states.
• In p-type Schottky contacts,electrons flow from
  the metal to semiconductor.

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Metal on n-type Semiconductor
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Metal on p-type Semiconductor.
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Temperature Vs Free carrier Concentration

• The regions on the curve are
• Freeze-out
• Depicts the unionized dopants
• Extrinsic Region
• Represents ionized dopants and control
  conductivity.
• Intrinsic Region
• Characterizes broken covalent bonds

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Basic Principles(cont)
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Physics Involved

• The intrinsic carrier concentration is calculated
• ni nio (T/To)1.5 exp (Eg / 2KTo) (1-
  To/T)
• ND1 ( Nd1/ (12Nd1/(NCO ni1.5) ) exp (( Ec
  Ed1)/KT)

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Conclusions

• Simulation of Schottky diodes using JAVA Applets
  is accomplished.
• Temperature Vs. Free carrier concentration curves
  for different semiconductors have been plotted.
• Applets have been successfully hosted on the
  World wide web.