_nitride.gif)
Indium(III) nitride
Encyclopedia
Indium nitride is a small bandgap semiconductor material which has potential application in solar cells and high speed electronics.
The bandgap of InN has now been established as ~0.7 eV depending on temperature (the obsolete value is 1.97 eV).
The effective electron mass has been recently determined by high magnetic field measurements
, m*=0.055 m0. Alloyed with GaN, the ternary system InGaN has a direct bandgap span from the infrared
(0.65 eV) to the ultraviolet
(3.4 eV).
Currently there is research into developing solar cells using the nitride
based semiconductor
s. Using the alloy indium gallium nitride
(InGaN), an optical match to the solar spectrum
is obtained. The bandgap of InN allows a wavelength
s as long as 1900 nm to be utilized. However, there are many difficulties to be overcome if such solar cells are to become a commercial reality. p-type doping
of InN and indium-rich InGaN is one of the biggest challenges. Heteroepitaxial growth of InN with other nitrides (GaN, AlN
) has proved to be difficult.
Thin polycrystalline films of indium nitride can be highly conductive and even superconductive at helium temperatures. The superconducting transition temperature Tc depends on the film structure and is below 4 K. The superconductivity persists under high magnetic field (few teslas) that differs from superconductivity in In metal which is quenched by fields of only 0.03 tesla. Nevertheless, the superconductivity is attributed to metallic indium chains or nanoclusters, where the small size increases the critical magnetic field according to the Ginzburg–Landau theory.
The bandgap of InN has now been established as ~0.7 eV depending on temperature (the obsolete value is 1.97 eV).
The effective electron mass has been recently determined by high magnetic field measurements
, m*=0.055 m0. Alloyed with GaN, the ternary system InGaN has a direct bandgap span from the infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
(0.65 eV) to the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
(3.4 eV).
Currently there is research into developing solar cells using the nitride
Nitride
In chemistry, a nitride is a compound of nitrogen where nitrogen has a formal oxidation state of −3. Nitrides are a large class of compounds with a wide range of properties and applications....
based semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
s. Using the alloy indium gallium nitride
Indium gallium nitride
Indium gallium nitride is a semiconductor material made of a mix of gallium nitride and indium nitride . It is a ternary group III/group V direct bandgap semiconductor. Its bandgap can be tuned by varying the amount of indium in the alloy...
(InGaN), an optical match to the solar spectrum
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
is obtained. The bandgap of InN allows a wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s as long as 1900 nm to be utilized. However, there are many difficulties to be overcome if such solar cells are to become a commercial reality. p-type doping
P-type semiconductor
A P-type semiconductor is obtained by carrying out a process of doping: that is, adding a certain type of atoms to the semiconductor in order to increase the number of free charge carriers ....
of InN and indium-rich InGaN is one of the biggest challenges. Heteroepitaxial growth of InN with other nitrides (GaN, AlN
Aluminium nitride
Aluminium nitride is a nitride of aluminium. Its wurtzite phase is a wide band gap semiconductor material, giving it potential application for deep ultraviolet optoelectronics.-History:...
) has proved to be difficult.
Thin polycrystalline films of indium nitride can be highly conductive and even superconductive at helium temperatures. The superconducting transition temperature Tc depends on the film structure and is below 4 K. The superconductivity persists under high magnetic field (few teslas) that differs from superconductivity in In metal which is quenched by fields of only 0.03 tesla. Nevertheless, the superconductivity is attributed to metallic indium chains or nanoclusters, where the small size increases the critical magnetic field according to the Ginzburg–Landau theory.