Indium gallium arsenide

Indium gallium arsenide (InGaAs ), also known as gallium indium arsenide is a semiconductor material and the name for a group of alloys from the two basic materials indium arsenide ( InAs ) and gallium arsenide (GaAs ). The alloy is one of the III -V compound semiconductors and is a semiconductor of direct application in the field of optoelectronics.

General

Depending on the mixing ratio of the two starting materials, it is sure a notation of the form In1 - x Ga x As where X indicates the mixing ratio, can alter the optical properties of the change of the band gap in the production of the material, as shown in the adjacent figure. A value of X = 0.47 indium is commercially available under the CAS number 106097-59-0, it can, however, make any other mixing ratios. X = 0, it is pure indium having a band gap of 0.34 eV at 300K and X = 1 for pure gallium arsenide, having a band gap of 1.42 eV.

Commercially available indium with a mixing ratio of x = 0.47 by means of crystal growth on a substrate of indium phosphide ( InP) single crystal as grown. The ratio results from the fact, because it matches the lattice constant of InP with the alloy of indium gallium arsenide. The band gap of In0, 53Ga0, 47As is 0.75 eV, and this alloy has a high electron mobility of nearly 10,000 cm2 · V-1 · s -1.

Applications

They are primarily used are infrared detectors such as photodiodes, with maximum sensitivity as a function of wavelength in the range from 1.1 microns to 1.7 microns. Unlike similar semiconductor materials such as germanium, which also has a high sensitivity in the infrared region, indium has a smaller dark current and a faster response time for the same detector size. First photodiodes based on indium gallium arsenide in 1977, developed by TP Pearsall and RW Hopson at Cornell University, New York.

Further applications of the material are due to the high electron mobility in so-called high- electron -mobility transistors ( HEMT). Transistors made of indium gallium arsenide count with a transit frequency of 600 GHz, the fastest transistors with applications in the field of terahertz radiation.