Why Are Wafers Colorful?


July 4, 2022

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A GaAs wafer has one notable feature – it can output colors when they reflect light. This effect on gallium arsenide wafers comes from three natural events that occur when light passes over a surface.

A closer look at colorful GaAs wafers

The Three Factors That Make Wafer Colors Possible

According to science, three factors allow the surface of a gallium arsenide or silicon wafer to output several hues. These are, namely, diffraction and interference.

Light Diffraction

Diffraction is an event where light waves bend around the edges of any surface. Light can also turn when it goes through a small vertical or horizontal opening. When the light diffuses, it also spreads out, revealing various colors. The colors represent the different bandwidths of light – the more visible color is, the longer length of the ray.  

Red is the most visible color in the spectrum because it has the longest wavelength. On the other hand, violet is rarely seen in a rainbow because its length is the shortest. Because of their wavelengths, other colors are not visible to the naked eye, including ultraviolet.


As the term suggests, interference is when light waves collide and affect each other. Individual light waves impose themselves on each other and either cancel or amplify one another. Light waves canceling each other is known as “destructive” interference. Its opposite is “constructive” interference, where light waves reinforce their visual manifestations.

Visually, constructive interference causes multiple colors to appear when light reflects on a surface. One example of this interference is the seven colors that come out of a prism.  


Iridescence is a result of interference. A surface is said to be iridescent if the colors it outputs are different when viewed from varying angles. For instance, you turn a germanium wafer to the right and see five colors. However, if you turn the wafer over to the left, you see only four colors. This is because one surface interferes with light differently from another.

Iridescence is mainly observed in insects like butterflies. However, several rocks also have light interfering properties that result in an iridescent surface.

worker handling a GaAs wafer

Turn to a Trusted GaAs Wafer Supplier

Our GaAs wafers undergo a stringent quality control process to ensure that you get wafers with the highest production yields. Contact us now for a quote.