InP Diodes - Transferred Electron Devices - Microwave Engineering

TL;DR

An InP diode is a transferred electron device whose n-type indium phosphide structure uses a three-valley energy model: lower, middle, and upper valleys. Its forbidden energy gap is 1.33 electron volts, while the middle and upper valleys occur at 0.6 and 0.8 electron volt relative to the conduction-band boundary. Read on to understand electron transfer, valley coupling, oscillations, and the resulting current-density drop.

Transcript

click the bell icon to get latest videos from akira hello Prince I welcome you all to this video we are with chapter 4 of micro-engineering a family of transferred electron devices where we are using a semiconductor compound structure and with respect to the energy levels as we have multiple energy levels the electrons are getting transferred from ... Read More

Key Insights

• 😒 InP diodes use indium phosphide as the semiconductor compound structure.
• 🎚️ The energy level structure of InP diodes consists of three levels: lower valley, middle valley, and upper valley.
• 💦 Increasing the applied electric field to InP diodes results in a threshold valley and a drop in conduction current density.
• 🔊 The peak to valley drop-down in InP diodes is higher than in gallium arsenide diodes.

Questions & Answers

Q: What is an InP diode in microwave engineering?

An InP diode is an indium phosphide diode belonging to the family of transferred electron devices. Electrons transfer between multiple energy levels as energy and an electric field are applied to the n-type indium phosphide material.

Q: How does an InP diode differ from an n-type gallium arsenide diode?

The n-type gallium arsenide model has two probable energy valleys: a lower valley and an upper valley. The n-type indium phosphide model has three: lower, middle, and upper valleys.

Q: What is the three-valley energy model of an InP diode?

The model describes electron movement through the lower, middle, and upper valleys in the conduction band. Electrons first move from the valence band to the lower valley, then can transfer to the middle valley and finally to the upper valley as they absorb more energy.

Q: What is the forbidden energy gap of n-type indium phosphide?

The forbidden energy gap between the valence band and conduction band is 1.33 electron volts. After absorbing that amount of energy, electrons can shift from the valence band to the conduction band’s lower valley.

Q: How much energy separates the valleys in an InP diode?

The middle valley is shown at 0.6 electron volt and the upper valley at 0.8 electron volt relative to the conduction-band boundary. Their difference is therefore 0.2 electron volt.

Q: Which energy valleys are more strongly coupled in an InP diode?

The middle valley is coupled more strongly to the upper valley than to the lower valley. The explanation attributes this to the 0.2-electron-volt difference between the middle and upper valleys.

Q: How does an applied electric field affect an InP diode?

As the electric field applied to the bulk n-type indium phosphide increases, electrons transfer among the lower, middle, and upper valleys. After a threshold value is reached, oscillations occur and electron drift velocity decreases, producing a drop in conduction current density.

Q: How does the peak-to-valley drop of an InP diode compare with a gallium arsenide diode?

The peak-to-valley drop is higher for the InP diode than for the gallium arsenide diode. This corresponds to a more significant decrease in conduction current density after the threshold region.

Summary & Key Takeaways

• InP diodes are part of the family of transferred electron devices and use the semiconductor compound structure of indium phosphide.

• These diodes have a different energy level structure compared to other diodes, with three energy levels instead of two.

• The oscillations and modes of operation of InP diodes are similar to other diodes, but with some differences due to the energy level structure.