BRIEF: A Brittle Crystal Becomes Flexible in the Dark

Scientists have just found out that zinc sulfide, a relatively common semiconductor material, becomes pliable when kept in the dark.
BRIEF: A Brittle Crystal Becomes Flexible in the Dark

Zinc sulfide crystal that shatters when compressed under light (upper right) is flexible if kept in the dark (lower right).

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Atsutomo Nakamura

Yuen Yiu, Staff Writer

(Inside Science) -- Researchers from Japan found that an otherwise brittle crystal becomes flexible when kept in complete darkness. Their discovery may help future scientists and engineers design devices previously thought impossible due to the brittleness of the semiconductor materials that are the fundamental building blocks for all modern electronics.

Scientists have long studied the effect of light on materials known as semiconductors -- they are often used in solar cells. But what about the effect of darkness? Looking for an answer, the researchers examined zinc sulfide, a relatively common semiconductor found in nature, first in light and later in complete darkness.

Under light, a pillar of zinc sulfide is brittle and prone to shatter into many pieces -- as one would expect of a crystal. But in the dark, an identical pillar of zinc sulfide becomes flexible, able to be squashed down to roughly half its original height without breaking. The crystal compressed in the dark also underwent changes to its electronic and optical properties.

Zinc sulfide belongs to a class of materials known as inorganic semiconductors, which, because of their unique electronic properties, have given birth to diodes, transistors and other important components of modern electronics. This discovery gives scientists and engineers another option when trying to tune or manufacture semiconductors with certain desirable properties.

A paper detailing the findings is published in the journal Science today.



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Yuen Yiu is a former staff writer for Inside Science. He's a Ph.D. physicist and fluent in Cantonese and Mandarin. Follow Yuen on Twitter: @fromyiutoyou.