Unit – 5
Low-Dimensional Optoelectronic Devices
Question and Answer
1) State and explain Quantum Well?
Answer:
A quantum well is a potential well with only separate energy values.
Lasers And Photo detectors.
Embracing one side of a 3-D plane until it is no thicker than one electron wavelength traps electrons in a 2-D plane.
In 2-D, the so-called density of states (the energy levels that electrons can occupy), becomes quantised.
After defining what layer thickness induces what energy level, researchers can design the exact characteristics of a material.
2) Draw a Quantum Wire Structure?
Answer:
3) Draw a Symbol of avalanche diode ?
Answer:
The symbol of avalanche and zener diode is similar. Avalanche diode contains of two terminals: anode and cathode. The symbol of avalanche diode is shown in underneath figure.
4) What is PIN Photodiode?
Answer:
The PIN photo diode operates with an realistic reverse bias voltageand when the reverse bias is applied, the space charge region must cover the intrinsic region totally.
Electron hole pairs are generated in the space charge region by photon absorption.
The swapping speed of frequency response of photodiode is inversely proportional to the life time.
5) What is Avalanche Photo Diode?
Answer:
Avalanche photo diode is a sympathetic of photo detector which can convert signals into electrical signals. The overhead figure is of Avalanche Photodiode. Avalanche photodiodes are used in applications where very sensitive light detection is required
6) Draw a diagram of Avalanche Photo diode?
Answer:
7) Define Solar cell?
Answer:
Solar cell, also called photovoltaic cell, any device that directly changes the energy of light into electrical energy through the photovoltaic effect.
The irresistible majority of solar cells are fabricated from silicon—with cumulative efficiency and lowering cost as the materials range from amorphous (non crystalline) to polycrystalline to crystalline (single crystal) silicon forms.
Unlike batteries or fuel cells, solar cells do not utilize chemical reactions or require fuel to produce electric power and unlike electric generators they do not have any affecting parts.
