BIOMEDICAL IMAGING: Inexpensive approach speeds photodetector used in medical imaging

An amorphous silicon (a-Si) metal-semiconductor-metal heterojunction photodetector with added molybdenum disulfide (MoS2) could boost the speed of medical imaging for minimal cost.1 MoS2 is sold as a lubricant in auto-parts shops.

Many photodetectors in large-area imaging devices use a-Si because it absorbs light well and is relatively inexpensive to process. But because the material inherently prevents fast, ordered movement of electrons, it operates more slowly, and thus allows greater exposure to radiation. The standard approach to improving performance has involved additional high-temperature processing, which adds to the cost of the imaging device.

University of California, Berkeley engineers Sayeef Salahuddin and Mohammad Esmaeili-Rad devised their solution by pairing a thin film of MoS2 with a sheet of a-Si. By forming a diode with the a-Si, the MoS2 allows the photogenerated electrons that it collects to travel through the a-Si 10 times faster. The detector has a photoresponsivity of 210 mA/W for green light, which is two to four times higher than usual for a-Si devices.

The researchers say that because these materials are easy to handle and inexpensive, the cost of speeding up photodetectors would be minimal. Unlike conventional semiconductors like Si, MoS2 consists of individual nanosheets that can be torn off like pages in a book. These sheets can be used to make thin, novel electronic devices or to improve existing ones.

1. M. R. Esmaeili-Rad and S. Salahuddin, Sci. Rep., 3, 2345 (2013); doi:10.1038/srep02345.

Get All the BioOptics World News Delivered to Your Inbox

Subscribe to BioOptics World Magazine or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now
Related Articles

Merz acquires laser tattoo removal device maker ON Light Sciences

Merz North America has acquired ON Light Sciences, which develops technologies to enhance laser-based dermatology procedures.

Shortwave-infrared device could improve ear infection diagnosis

An otoscope-like device that could improve ear infection diagnosis uses shortwave-infrared light instead of visible light.

Laser therapy extracts rare tumor that grew human hair, skin in boy's skull

About four years ago, a tumor comprised of human skin, hair, bone and cartilage was fast-growing inside a Ramsey, MN, 10-year-old youth's brain.

Low-level laser therapy could speed muscle recovery at Rio 2016 Olympics

The gold medal-winning women’s U.S. Gymnastics team is reportedly experimenting with infrared light therapy to alleviate pain and reduce swelling in its athletes. (Update: A spokesperson for ...

Neuro15 exhibitors meet exacting demands: Part 2

Increasingly, neuroscientists are working with researchers in disciplines such as chemistry and p...

Why be free?

A successful career contributed to keeping OpticalRayTracer—an optical design software program—fr...

LASER Munich 2015 is bio-bent

LASER World of Photonics 2015 included the European Conferences on Biomedical Optics among its si...

White Papers

Understanding Optical Filters

Optical filters can be used to attenuate or enhance an image, transmit or reflect specific wavele...

How can I find the right digital camera for my microscopy application?

Nowadays, image processing is found in a wide range of optical microscopy applications. Examples ...



Twitter- BioOptics World