Researchers Study Electronic Behavior of Atomically Thin Nanomaterials

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Researchers study the electronic behavior of atomically thin nanomaterials using scanning photocurrent microscopy, according to a study conducted on May 23, 2018.

This study was conducted by the researchers at the Center for Functional Nanomaterials (CFN), which is U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory.

Along with nanoscale optical imaging, the scanning photocurrent microscopy technique provides a powerful tool to understand the process that is affecting the photocurrent generation in these materials. It helps in improving the performance of solar cells, optical sensors, light-emitting diodes (LEDs), and other optoelectronics.

An electric current is generated by the semiconductor when light falls on it. The next-generation of optoelectronics will be interested in semiconductors that has one layer or a few layers of atoms. This is due to their sensitivity to light, which can controllably alter their electrical conductivity and mechanical flexibility. However, the atomically thin semiconductors can only absorb a limited amount of light, which limits the materials’ response to light.

Scientists added tiny semiconducting particles known as quantum dots into the layers of the semiconductor to enhance the light-harvesting properties of these materials. This enhanced the light harvesting properties and also developed interactions at the interface where the two components meet. The charge or energy is transferred to the 2D material by the light-excited quantum dots based on the size and composition.

Mircea Cotlet, co-corresponding author said, “Photodetectors sense an extremely low level of light and convert that light into an electrical signal. On the other hand, photovoltaic devices such as solar cells are made to absorb as much light as possible to produce an electrical current. In order to design a device that operates for photodetection or photovoltaic applications, we need to know which of the two processes — charge or energy transfer — is beneficial.”

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