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APPLICATION OF SEMICONDUCTOR IN DAILY LIFE

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Nur Fadhilah

on 6 April 2015

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Transcript of APPLICATION OF SEMICONDUCTOR IN DAILY LIFE


SOLAR
CELLS

GAS SENSOR TO QUALITY CONTROL OF MEAT FRESHNESS IN FOOD INDUSTRY
LASERS
GAS SENSORS FOR
MEDICAL DIAGNOSTICS
APPLICATION
OF SEMICONDUCTOR IN DAILY LIFE
INTRODUCTION
CLASSICAL
PHYSICS
MODERN
PHYSICS
W.Smith
1873 - discovered photoconductive effect in selenium
K.F Braun
1900-1905 - detector demodulation of - radiotelegraph
- radiotelephone signal

1920-1926 - invented: - copper oxide rectifier
- selenium rectifier
- photoelectric cell

1922 - crystal detector

1948 - transistor invented
development of semiconductor electronics became possible as a result of fundamental achievement in :
- quantum physics
- solid state physics
- semiconductor physics

semiconductor electronic properties and processes:
simultaneous existence of charge carriers of 2 signs, conduction electrons being the negative carriers and the holes is the positive carriers.
high sensitivity of light, heat and magnetic field.
undirectional conductivity for current passing through barriers layer of p-n junction.
tunneling of carriers through the potential barrier.

Improvement of electronic equipment on the basis of advances in semiconductor electronics
SOLAR
CELL

LASERS
GAS SENSOR TO QUALITY CONTROL OF MEAT FRESHNESS IN FOOD INDUSTRY
GAS SENSORS
FOR
MEDICAL DIAGNOSTICS
solar cell?
An electrical device that converts the
energy of light

electricity
by the photovoltaic effect.
It is a form of photoelectric cell, which have the electrical characteristics such as current, voltage or resistance.
These characteristics vary when exposed to light.
disadvantages
how it works?
Photon strike element ( semiconductor )
Energy of photons is absorbed by the electron thus rising a free electron
The free electron from an electric current and do useful works such as :
advantages
Reduce the cost of solar cell (semiconductor is cheap)
Reduce the mass (thin-film deposit of semiconductor)
Efficiencies of thin-film solar cell is lower than wafer-based solar cell
Amorphous silicon is not stable
Increased toxicity
one of the examples...?
carbon nanotubes (CNTs)
have been successfully applied in pharmacy and medicine
it plays a vital role in :
ITS STRUCTURE...
carbon nanotubes (CNTs) which are allotropes of carbon, made of graphite and constructed in cylindrical tubes.
with nanometer in diameter and several millimeters in length
ITS FUNCTIONS...
uses of semiconductor
of gas sensor
Examples?
Electric Nose
Detect & recognize items on the basis of their odor signature (gas detection).
Consists of an array of electrochemical and semiconductor sensor.
Convert : Chemical quantity
Electrical signal
How it
works?
Reducing gas interact with surface of these semiconductors and donate or release e- bound by absorbed oxygen
Results in drastic increase in surface conductivity while for an oxidising gas the conductivity will decrease
Be controlled by their operating temperature & by the film thickness or catalytic additives
Advantages
Very effective
Time consuming

Faster and applicable to the real-time identification of spoiled meat
quality control, process monitoring, freshness evaluation, shelf life investigation, and authenticity assessment
Why it is done
Food product quality control is one of the most actual and promising areas
In need in development of a more rapid method with higher sensivity in meat industry
SEMICONDUCTOR LASER ?
consist of complex multi-layer ( required nanometer scale accuracy and elaborate design)
small in size and appearance
structure - designed to keep the threshold low with high efficiency and a narrow output beam
material used - gallium Arsenide
HOW ITS WORK ?
light emission process and laser action
carrier recombination and spontaneous emission
the evolution of mode spectrum and intensity with current
Metal contact t connect p-n material to the DC power supply
At the junction - light is emitted when the electrons or current pass from N to P type material
Lasing - needed minimum current density
CHARACTERISTICS
REFLECTIVITY
Does no need mirror to obtain reflectivity to produce feedback mechanism
TEMPERATURE
Gives affect to the output of laser
When temperature increase power loss within the laser
ADVANTAGES
smaller size
the cost are economical
have high efficiency
DISADVANTAGES
Not suited to many typical application
Greatly dependent on temperature
Lasing medium is too short - the output beam profile has no fixed shape
generation ?
1st :
solar cell made using crystalline silicon wafer
2nd :
Amorphous silicon cell on stailess steel
Polycrytalline silicon
Copper indium gallium diselenide (CIGS) alloy cells
- drug and genes therapies
- biosensors
- tissue regeneration
- analysis of drugs
Hence, any medical diagnosis using the exhaled breath needs gas sensors with a very high degree of selectivity.
Traces of Nitric Oxide, NO,

changes in NO levels can indicate heart failure, asthma or even neuron death cased by degenerative diseases for instance, Alzheimer.
Detections of Volatile organic compound (VOC)
in human breath can be a symptom of kidney failure, diabetes, asthma or even breast cancer.
First generation
Equipment using electron tubes
Second generation
Equipment using discrete semiconductor devices. Example: junction diodes and transistors. The appearance of these electronic equipment made it possible to reduce factor of weight, size, power consumption and improve operating reliability
Third generation
Electronic equipment using integrated micro circuity. Example: various electric-conversion and optical-electronic
1874 - discovered the conductivity of a metal-semiconductor contact
Full transcript