The dramatic size reduction in conjunction with the significantly increased energy density achieved in this electro-optic memory cell is what allowed the researchers to bridge the apparent incompatibility of photons and electrons for data storage and computation. More specifically, they demonstrated that by sending either electrical or optical signals, the GST nanogap was transformed between two different states of molecular order, which could be read out by either light or electronics thereby making the device the first electro-optical nanoscale memory cell with non-volatile characteristics.
Optical programming of the PCM memory cell is performed with optical write and erase pulses that partially amorphize and crystallize the GST within the nanogap. Likewise, electrical write and erase pulses can be used to switch the GST between its amorphous and crystalline states, which can then be read out both optically and electrically by monitoring the material’s optical transmission and electrical resistance simultaneously.
"This is a very promising path forward in computation and especially in fields where high processing efficiency is needed" said Nikolaos Farmakidis, graduate student and co-first author of the paper.
"This naturally includes artificial intelligence applications where in many occasions the needs for high-performance, low-power computing far exceeds our current capabilities. It is believed that interfacing light-based photonic computing with its electrical counterpart is the key to the next chapter in CMOS technologies", added co-author Nathan Youngblood.
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