Indium arsenide
Indium arsenide, InAs, or indium monoarsenide, is a narrow-bandgap semiconductor composed of indium and arsenic. It has the appearance of grey cubic crystals with a melting point of 942 °C. Indium arsenide is similar in properties to gallium arsenide and is a direct bandgap material, with a bandgap of 0.35 eV at room temperature. Indium arsenide is used for construction of infrared detectors, for the wavelength range of 1–3.8 µm. The detectors are usually photovoltaic photodiodes. Cryogenically cooled detectors have lower noise, but InAs detectors can be used in higher-power applications at room temperature as  well. Indium arsenide is also used for making of diode lasers. InAs is well known for its high electron mobility and narrow energy bandgap. It is widely used as terahertz radiation source as it is a strong photo-Dember emitter. The optoelectronic properties and phonon vibrations are slightly changed under the effect of temperature over the range form 0 K to 500 K. Ternary and quaternary compounds. Indium arsenide is sometimes used together with indium phosphide. Alloyed with gallium arsenide it forms the ternary semiconductor indium gallium arsenide (InGaAs), a material with band gap dependent on In/Ga ratio. Indium  arsenide is sometimes alloyed with indium phosphide and Indium antimonide to create a quaternary alloy with a range of band gaps that depend on the different concentration ratios of its components (InP, InAs and InSb), such quaternary alloys was under extensive theoretical studies to study the effect of pressure on its properties. Quantum dots can be formed in a monolayer of indium arsenide on indium phosphide or gallium arsenide. The mismatches of lattice constants of the materials create tensions in the surface layer, which in turn leads to formation of the quantum dots. Quantum dots can also be formed in  indium gallium arsenide, as indium arsenide dots sitting in the gallium arsenide matrix.