When thinking about the semiconductors within our computers and other devices, as we surely do at times, chances are we just think about silicon, but there are more materials than that one involved. On its own, silicon actually will not conduct electricity, which is why other molecules called dopants are added to the material, but adding too many doping molecules will eventually block the electrical currents. The cause of this increased resistance is believed to be from the electrons bouncing off of the dopants, but now researchers at the University of Illinois at Chicago have discovered another mechanism that increases resistance.
To make this discovery the researchers started with chips of cadmium sulfide for their semiconductor base and then used copper ions as the dopant. Instead of connecting the chips up run a current through them, the researchers instead shot a powerful blue laser at them, with the energy of the laser being enough to generate an electrical current. Very high energy X-ray images were taken at the same time just millionths of a microsecond apart to reveal what was going on. To the researchers' surprise, the copper ions were intermittently forming bonds with the semiconductor base, and these bonds were then impairing conduction.
This behavior has not been seen before and it would be impairing the speed and efficiency of the semiconductor computers it affects. Fortunately, now that we are aware of this dynamic it will be possible to create designs that minimize it.
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