A schematic shows the design of an optoelectronic memory device based on CIS. The device traps electrons formed when light hits the material and holds them until released for storage. (Image Credit: Ajayan Group/Rice University)
With microscale or nanoscale devices, one of the bottlenecks is the CCD part. There are two-dimensional field-effect transistors and logic circuits, but you don’t have the image capture part, which is very important. You want to make the image capture part compatible with the other parts. That means if you use a 2D material to fabricate a CCD, you can very easily implant this kind of material in the normal electronics.

The material will also work with silicon-based traditional electronics and traditional platforms. You can put this copper indium selenide CCD in the silicon-based device. The purpose of this layered CCD, the flexibility, is to implant this kind of sensor on future flexible devices. You want to make the whole device flexible and highly integrated.

IT: What is next for the technology?

Lei: We still want to enhance the response of the materials. We are working on some modifications to improve the overall performance. Right now we have a three-pixel prototype. We want to make an even larger matrix, probably 10 x 10 or even larger, so you can take some very complex images.