<< Chapter < Page Chapter >> Page >

In 1980’s with the development of low attenuation optical fiber , short haul-heavy traffic and long haul communication turned towards Optical Fiber Communication. In communication there is a heavy premium on Band Width and Optical fiber could offer immense amount of BW at very low cost. This gave a tremendous boost to R&D in optoelectronic devices and optoelectronic chips. The material of choice could only be Compound Semiconductors and their alloys. The compound semiconductors are direct band-gap materials offering high radiative quantum efficiency.

Indium Antimonide (InSb) was the first III-V compound semiconductor to be discovered in 1950. Because of narrow band-gap, E g = 0.17eV, InSb is the suitable material for fabricating optoelectronic devices in far infrared spectrum because 0.17eV band-gap corresponds to critical wavelength λ c = (1.24/ E g )= 7.3μm. This critical wavelength will decide the optical emission and absorption wavelength.

The invention of semiconductor laser and the discovery of Gunn-Effect brought GaAs ( E g = 1.43eV) and InP ( E g = 1.35eV) to a position of eminence. The need for visible light Light Emitting Diodes by necessity led to the importance of GaP( E g =2.1 eV) and its alloys. 2.1eV band-gap corresponds to a critical wavelength of 0.59μm which falls in visible part of the spectrum. By suitable alloying , any critical wave length in the range 0.4μm to 0.7 μm can be achieved and 0.4μm to 0.7 μm is the visible part of the spectrum. The alloying process, to achieve a suitable critical wavelength, is known as BAND-GAP ENGINEERING. We will deal with this topic in PHOTONICS Chapter.

The choice of different Binary Compounds provides us a wide range of Band-gaps ranging from InSb of band-gap 0.17eV to SiC of band-gap 2.99eV. SiC enabled the fabrication of Blue Laser diodes which are used to sense the pixels of DVD (Digital Versatile Disc). The advent of DVD has greatly enhanced the storage capacity. CD stores 700MB whereas DVD stores 4GB and more.

Here it may also be pointed out that Extreme Ultra-Violet photolithography is enabling the fabrication of nano-electronics chips or realization of lateral feature size less than 100nm as required in Ultra-Large-Scale-Integrated (ULSI) Chips. This again is dependent upon research in very wide band-gap material typically a band-gap of 12.4eV corresponding to a critical wavelength of 0.1μm.

The ease of alloying Binary Compounds into Ternary Compounds such as AlGaAs and Quaternary Compound such as InGaAlAs makes the use of compound semiconductor in photonics very attractive and convenient.. The alloyed Binary compounds gives a continuous and monotonic variation in Band-gap energy according the stoichometric coefficient of the alloyed material. This continuous variation gives the Photonic Scientists a more varied option in terms of band-structure, electronic properties and optical properties. The alloying process can be achieved by Molecular Beam Epitaxy(MBE). This alloying process also enables the fabrication of Hetrostructure Junctions which is much more power efficient as compared to Homojunctions. Homojunctions are junctions formed by P type and N Type of same material whereas Hetrojunctions are formed by P Type and N Type of different materials. Table(1.26) tabulates the electronic properties of Compound Semiconductors.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Solid state physics and devices-the harbinger of third wave of civilization' conversation and receive update notifications?

Ask