Extrinsic Semiconductor
Chapter Name : Semiconductor Electronics: Materials, Devices And Simple Circuits |
Sub Topic Code : 101_12_14_04_01 |
Topic Name : Extrinsic Semiconductor |
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Sub Topic Name : Extrinsic Semiconductor |
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Introduction
Electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors.
Pre-Requisites:
Semiconductor
Activity:
Silicon (Si) is the most widely used material in semiconductor devices.
Real Life Question:
What is Extrinsic Semiconductor?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Extrinsic Semiconductor | Doped semiconductors (either n-type or p-type) are known as extrinsic semiconductors. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| microprocessors | All transistor types can be used as the building blocks of logic gates, which are fundamental in the design of digital circuits. Transistors act as on-off switches; in the MOSFET, for instance, the voltage applied to the gate determines whether the switch is on or off. |
Real life uses :
Building circuits.
Places to visit :
Digital circuits
Practical examples around us
| Examples | Explainations |
|---|---|
| Solar cell | Electrical device that converts the energy of light directly into electricity by the photovoltaic effect. |
What you learn in Theory:
In an extrinsic semiconductor there is an contribution to the total number of charge carriers from intrinsic electrons and holes, but at room temperature this contribution is often very small in comparison with the number of charge carriers introduced by the controlled impurity doping of the semiconductor.
What you learn in Practice:
The activation energy for electrons to be donated by or accepted to impurity states is usually so low that at room temperature the concentration of majority charge carriers is similar to the concentration of impurities.