Gallium Uses in Technology
By Robert Ploessl, Indium Corporation
In our modern world gallium is used everywhere, and modern life would be unrecognizible without the benefits it provides.
As you are reading this, the nearest gallium (Ga) atoms are most likely found inside the computing device that is within your arm’s reach. WiFi and Bluetooth devices inside today’s laptops, cell phones, and tablets use gallium arsenide (GaAs) semiconductors that utilize its properties to build radio frequency integrated circuits. In recent years, chargers for mobile devices have become much smaller while also providing more power and faster charging cycles because they use gallium nitride (GaN) power semiconductor chips.
In its elemental form, gallium melts at close to 30°C; it is liquid just above room temperature. When alloyed with indium, the resulting melting point is below room temperature and lowered further when adding tin. Their low melting points have made the gallium alloy family a non-toxic replacement for mercury in applications that require a liquid metal at room temperature. Liquid metals are becoming increasingly studied for thermal interface applications where heat needs to be transported away from hot semiconductor chips.
When incorporated into III-V semiconductors (GaAs, GaN, GaP, and others), the electronic and optical properties of these materials render them superior to silicon, although at a higher cost. While the electronic band structure of Ga-based semiconductors provides for much higher switching speeds, any commercial application must balance this against the lower integration cost of silicon to manufacture integrated circuits.
The main industrial uses of gallium metal today are:
- Semiconductor applications, such as integrated circuits, LEDs, and quantum dots
- In material systems (GaAs, GaN, GaP)
- In crystal wafers and gallium MOCVD precursors (TMG, TMGa)
- As metallic gallium for liquid phase epitaxy and gallium trichloride for TMG/TMGa manufacturing
- Electric vehicles and wind power generators
- In strong magnets that use Ga as a dopant
- Solar photovoltaics
- As a p-dopant in silicon-based solar cells
- In thin-film solar cells that combine gallium with indium, copper, and selenium (CIGS)
- Specialty batteries
- In the electrolyte of high-temperature lithium thionyl chloride batteries
- LCD and OLED displays
- As gallium oxide for part of the IGZO (indium gallium zinc oxide) films to form the transistors that control the switching of pixels in the display backplane
You can see that gallium and its compounds have an amazing number of industrial uses and unique and intriguing properties when compared to other elements. An interesting and fun read is The Disappearing Spoon (https://www.amazon.com/Disappearing-Spoon-Madness-Periodic-Elements/dp/0316051632) by Sam Kean. This book has fascinating and unusual stories about groups of elements found on the periodic table, but the title of the book is directly related to gallium. And, to see a disappearing spoon in action, view the video here: https://youtu.be/t3tpj9hVbJU