Indium sulfide is the inorganic compound

Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

 In₂S₃. Three different structures ("polymorph

Polymorphism (materials science)

Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...

s") are known: yellow, α-In₂S₃ has a defect cubic structure, red β-In₂S₃ has a defect spinel, tetragonal, structure, and γ-In₂S₃ has a layered structure. The red, β, form is considered to be the most stable form at room temperature, although the yellow form may be present depending on the method of production. Like related covalent solids, In₂S₃ is insoluble

Solubility table

The table below provides information on the variation of solubility of different substances in water with temperature, under 1 atm pressure, units of solubility in g/100g H2O...

 in all solvents. It is attacked by acids and by sulfide. It is slightly soluble in Na2S.

Indium sulfide was the first indium compound ever described, being reported in 1863. Reich and Richter determined the existence of indium as a new element from the sulfide precipitate.

Structure and properties

In₂S₃ features tetrahedral In(III) centers linked to four sulfido ligands. β-In₂S₃ is a diamagnetic, n-type semiconductor

N-type semiconductor

N-type semiconductors are a type of extrinsic semiconductor where the dopant atoms are capable of providing extra conduction electrons to the host material . This creates an excess of negative electron charge carriers....

 with an optical band gap

Band gap

In solid state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference between the top of the valence band and the...

 of 2.1 eV. It has been proposed to replace the hazardous cadmium sulfide

Cadmium sulfide

Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid. It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores...

, CdS, as a buffer layer in solar cells.

Production

Traditionally it was prepared in the chemical laboratory by direct combination of the elements. Production from volatile complexes of indium and sulfur for example dithiocarbamates (e.g. Et₂In^IIIS₂CNEt₂) have been explored as methods suitable for vapor deposition

Chemical vapor deposition

Chemical vapor deposition is a chemical process used to produce high-purity, high-performance solid materials. The process is often used in the semiconductor industry to produce thin films. In a typical CVD process, the wafer is exposed to one or more volatile precursors, which react and/or...

techniques.