IIT-B develops ultra-thin optical sensor for wearable electronics

HT Image
HT Image
Published on Jul 19, 2020 11:21 PM IST
Copy Link
ByPriyanka Sahoo, Mumbai

A team of researchers from Indian Institute of Technology-Bombay (IIT-B) developed an ultra-thin next-generation optical sensor prototype that can be used for applications such as bioimaging, wearable electronics, environmental monitoring, defence and telecommunications.

Optical sensors, such as photodetectors, can convert rays of light into electronic signals. These sensors are used as optical switches in telecommunication, for capturing images in defence and biomedical equipment, as toxic gas monitors for pollution control, as well as photovoltaic cells for renewable power generation.

However, conventional optical sensors currently in use are made from thick silicon or III-V compound semiconductors which make them power hungry. Hence, they are difficult to use in emerging applications such as wearable devices, flexible electronics, and multi-sensor networks for the internet-of-things (IoT).

The researchers at IIT-B, led by Saurabh Lodha, professor, department of electrical engineering, designed a prototype of ultra-thin optical sensors using graphene-like two-dimensional (2D) materials that has high optical sensitivity and can also generate power. The prototype overcomes the limitations of conventional optical sensors owing to the exceptional electronic, mechanical, and optical properties of these 2D materials.

Their study was published in the American Chemical Society’s monthly peer-reviewed journal Nano Letters in February.

“We conductedseveral rounds of theoretical calculations before we started work on the prototype. The thickness of the materials was critical. We found that two specific materials from the graphene family, when stacked on top of each other with the right thicknesses, form a heterojunction that results in excellent optoelectronic performance and enables broadband light detection from visible to infra-red, which is not possible with the individual materials,” said Lodha, the principal investigator of the project.

“The recent work from IIT-B is of great interest to the device community; it is expected to give a new direction to this field because it exploits the light sensing and energy harvesting potential at the junction of two dissimilar 2D materials which are just a few atomic layers thin. We call it “interlayer band gap” and, to my knowledge, no one has investigated or reported it earlier to show promising solar cell behaviour and ultrafast photodetectors,” said Digbijoy Nath, assistant professor, Centre for Nano Science and Engineering (CeNSE) at the Indian Institute of Science (IISc), Bangalore, who was not a part of the research.

The theoretical calculations were conducted at IIT-B with inputs from Monash University, Australia, and the prototype was fabricated at IIT-B’s Nanofabrication Facility. Key theoretical predictions of the sensors were experimentally verified in collaboration with the Tata Institute of Fundamental Research, Mumbai, said Abin Varghese, PhD student and first author of the study.

“Most of the research on photodetection using low-dimensional materials focusses on enhancing one or two performance parameters, typically at the expense of other metrics. However, it is the multi-functional excellence of this heterostructure platform that makes it promising and brings us a step closer to the real-world technologies”, said Lodha.

“In the future, we plan to take this work forward from lab-to-fab using wafer-scale material growth techniques. Then, we plan to integrate optical, gas and thermal sensors to build an energy-efficient IoT sensor network,” he added.

SHARE THIS ARTICLE ON
Close Story
QUICKREADS

Less time to read?

Try Quickreads

  • The accused had snatched a pedestrian’s mobile phone in Mohali. (Representative image)

    Two mobile snatchers arrested in Mohali

    The Phase-8 police have arrested two men for snatching a pedestrian's mobile phone in Mohali on Wednesday. The accused have been identified as Iqbal Singh, a resident of Ludhiana, and Swaran Khan of Sohana. Seventeen mobile phones they had snatched and a stolen bike have been recovered from them. The complainant, Anil Kumar, told police that his mobile phone was snatched at the Sector 68/69 lightpoint by two men on Wednesday.

  • The trials will be held on the ground of Government Model Senior Secondary School, Sector 19, Chandigarh. (Representative image)

    Chandigarh Cricket Academy to conduct trials on May 23

    The Chandigarh Cricket Academy, Sector 19, will conduct trials at 6 am on May 23 for U-12 to U-19 boys and girls for the upcoming season intake. No trial fees will be charged from the participants. The director of the academy, Surinder Singh Baijee, who was previously secretary of the Chandigarh Cricket Association, affiliated to Haryana Cricket Association, aims to train the local cricketers to bolster the level of the sport in Chandigarh.

  • Officials launching the helmet bank at the Chandigarh MC office on Thursday. (HT Photo)

    Helmet bank launched for Chandigarh MC employees

    Mayot Sarbjit Kaur on Wednesday launched a “helmet bank” for employees of Chandigarh MC at the civic body's office under the road safety project, “Sadak”, undertaken by the NGO . The NGO has donated 100 helmets to MC and employees can get them issued from the bank and return them when they don't need it anymore.

  • Chandigarh MC commissioner says those violating norms are being challaned regularly, but the civic body’s cattle pounds are already filled to the brim. (Sanjeev Sharma/HT)

    Chandigarh residents decry MC’s failure to reel in cattle menace

    The cattle menace is a commonplace complaint for city residents, with strays having become a major traffic hazard in several sectors. The southern belt of the city, particularly, Sectors 38, 39, 42 and 52, are facing an acute problem of not only the stray cattle but also people from nearby villages leaving their domesticated animals to roam freely in the areas.

  • Now, execution of lease deed/conveyance deed and transfer of built-up units is being allowed even in matters where show-cause notice for building violations has been issued. (HT File)

    Building violations: Chandigarh Housing Board to expedite pending applications for property transfer

    The Chandigarh Housing Board has decided to finalise through a mission mode all pending applications for property transfer in cases where show-cause notices have been issued for building violations. All applications, which were filed before March 31, 2022, will be covered under the mission. Recently, CHB decided to delink building violations from execution of lease deed/conveyance deed and transfer of residential units.

SHARE
Story Saved
×
Saved Articles
Following
My Reads
Sign out
New Delhi 0C
Friday, May 20, 2022