Introduction

Semiconductors can made into any of a large number of devices with wide ranging applications and are used extensively in commerce and industry as well as everyday life. The following devices are all widely used or the subject of current research.

Metal-Semiconductor Junctions and Semiconductor Heterojunctions

Main Article: Metal-Semiconductor Junctions and Semiconductor Heterojunctions

The most basic devices consist of the regions where metal and semiconductor materials meet, used as electrical contacts and structures made up of two layers of semiconducting material with differing bandgaps.

p-n Junction

Main Article: p-n Junction

A p-n junction is the interface between n-type and p-type semiconductor layers and forms the basis of many other semiconductor devices.

Solar Cell

Main Article: Solar Cell

The solar cell consists of a p-n junction and uses the photovoltaic effect to convert incident light into electrical energy. The main appication of the cell is as a renewable source of electricity.

Light Emitting Diode

Main Article: Light Emitting Diode

The Light Emitting Diode (LED) is another p-n junction device that emits photons when electricity is inputted. The colour of the photons emitted is dependent on the semiconductor materials used.

Transistors

Metal Semiconductor Field Effect Transistor (MESFET)

Main Article: MESFET

Metal Oxide Semiconductor Field Effect Transistor (MOSFET)

Main Article: MOSFET

Transistors are layered semiconductor structures whose responses to electrical inputs make them vital to integrated cicuits and hence modern computing technology.

Resonant Tunnelling Diode

Main Article: Resonant Tunneling Diode

The Resonant Tunnelling Diode (RTD) is a layered semiconductor structure that forms a quantum well in which electron tunnelling takes place. The device produces a negative differential resistance effect, where surrent decreases as the applied voltage is increased.

Spintronics

Main Article: Spintronics

The field of spintronics involves the combination of semiconductors and magnetic materials to allowe the spin states of an electron to be manipulated. It has appications in computer storage and memory and potentially transistors.

Electronic Cooling Junctions

Main Article: Electronic Cooling Junctions

These devices reside on chips and use direct electron cooling to achieve sub-Kelvin temperatures as well as incorporating superconductors.

Light Emitting Diodes

Metal -Semiconductor and Semiconductor HeteroJunctions

Resonant Tunnelling Diode

p-n junction

MESFET

MOSFET

Spintronics

Solar cells

Electronic cooling junctions