Opto electronics devices

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  • Optoelectronics is the study area lies at combination between electronics and optics. It is based on the quantum mechanical effects of light on the semiconductor material. The optoelectronic devices functions as electrical to optical or optical to electrical transducers.
  • LED is the device used to emit light when it is applied electrical bias. The condition for the emitting is that it must be applied a electric bias. The emission light color depends on the composition of the semiconductor material used. Now let’s look at how light is generated in LED. The light can be infrared, visible and UV light.
  • In semicondutor, after the electron is excited to higher energy level, it can only stay in certain enregy band, range
  • Opto electronics devices

    1. 1. Introduction to Optoelectronic Devices G.Aarthi Assistant Professor / SENSE VIT University Email: aarthi.g@vit.ac.in
    2. 2. Outline <ul><li>What is optoelectronics? </li></ul><ul><li>Major optoelectronic devices </li></ul><ul><li>Current trend on optoelectronic </li></ul><ul><li>devices </li></ul>
    3. 3. What Did the Word “Opto-Electronics” Mean? <ul><li>Optoelectronics is the study and application of electronic devices that interact with light </li></ul>Electronics (electrons) Optics (light or photons) Optoelectronics
    4. 4. Examples of Optoelectronic Devices
    5. 5. Major Optoelectronic Devices ─ Direct Conversion Between Electrons and Photons <ul><li>Light-emitting diodes (LEDs) </li></ul><ul><li>(display, lighting,···) </li></ul><ul><li>Laser diodes (LDs) </li></ul><ul><li>(data storage, telecommunication, ···) </li></ul><ul><li>Photodiodes (PDs) </li></ul><ul><li>(telecommunication, ··· ) </li></ul><ul><li>Solar Cells </li></ul><ul><li>(energy conversion) </li></ul>
    6. 6. Light-Emitting Diodes (LEDs) Light-emitting diode ( LED ) is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction.
    7. 7. Photon Emission in Semiconductor When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The wavelength of the light depends on the band gap of the semiconductor material Semiconductor materials: Si, Ge, GaAs, InGaAs, AlGaAs, InP, SiGe, etc E F E C E V Conduction band Valence band Photon E g
    8. 8. Semiconductor Materials vs. LED Color General Brightness GaP GaN GaAs GaAIAs -- Green , Red Blue Red , Infrared Red , Infrared -- Super Brightness GaAIAs GaAsP GaN InGaN GaP Red Red , Yellow Blue Green Green Ultra Brightness GaAIAs InGaAIP GaN InGaN -- Red Red , Yellow , Orange Blue Green --
    9. 9. Application of LEDs <ul><li>Display </li></ul><ul><li>Solid-state lighting </li></ul><ul><li>Communication </li></ul><ul><li>Remote control, etc </li></ul>LED lights on an Audi S6
    10. 10. Laser Diodes (LDs) Lasers (Light Amplification by Stimulated Emission) Photon emission processes: Absorption Photodetectors Spontaneous emission LEDs Stimulated emission Lasers
    11. 11. Photo Diodes (PDs) A photodiode is a semiconductor diode that functions as a photodetector. It is a p-n junction or p-i-n structure. When a photon of sufficient energy strikes the diode, it excites an electron thereby creating a mobile electron and a positively charged electron hole
    12. 12. PDs’ Detection Range and Materials Material Wavelength range (nm) Silicon (Si) 190–1100 Germanium (Ge) 400–1700 Indium gallium arsenide (InGaAs) Lead sulfide (PbS) 800–2600 <1000-3500
    13. 13. Vision of Solar Cells (Photovoltaics) Solar Energy <ul><li>Free </li></ul><ul><li>Essentially Unlimited </li></ul><ul><li>Not Localized </li></ul>Solar Cells <ul><li>Direct Conversion of Sunlight  Electricity </li></ul><ul><li>No Pollution </li></ul><ul><li>No Release of Greenhouse-effect Gases </li></ul><ul><li>No Waste or Heat Disposal Problems </li></ul><ul><li>No Noise Pollution — very few or no moving parts </li></ul><ul><li>No transmission losses — on-Site Installation </li></ul>Why solar cells?
    14. 14. Residential and Commercial Applications Challenges: cost reduction via: a) economy of scales b) building integration and c) high efficiency cells
    15. 15. Trends in optoelectronic devices <ul><li>Long wavelength, high power light sources or </li></ul><ul><li>photodetectors </li></ul><ul><li>Nanoscale devices </li></ul><ul><li>Low cost, easy fabricated materials </li></ul><ul><li>High opto-electronic conversion efficiency </li></ul><ul><li>Multi-wavelength sources </li></ul>
    16. 17. Advantages of Optical Comm.

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