The sensors are integrated in a 100-micron sized package containing a silicon IC, photovoltaic converter and inorganic light emitting diodes. The devices have been used to record and report voltage, temperature, pressure and conductivity in a variety of environments.
The devices are fabricated, packaged, and released in parallel using photolithographic techniques, resulting in 10,000 individual sensors per square inch. With production volumes of up to 1 million sensors per 200mm-diameter wafer, each device would be expected to cost less than 1 cent each.
To transfer the LEDs to the silicon wafer the researchers developed an assembly method that requires more than 15 photolithography definitions, 30 different materials and more than 100 steps.
In order to transfer the LEDs to a wafer with the electrical components and integrate them, the researchers developed a complicated assembly method that involved more than 15 layers of photolithography, 30 different materials and more than 100 steps.
The team's paper, "Microscopic sensors using optical wireless integrated circuits," was published in the Proceedings of the National Academy of Sciences of the United States of America on April 17.
The collaboration is led by Paul McEuen, professor of physical science, and Alyosha Molnar, associate professor of electrical and computer engineering. Working with the paper's lead author, Alejandro Cortese, a Cornell Presidential Postdoctoral Fellow, they devised a platform for parallel production of their optical wireless integrated circuits (OWICs)
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