Loading...
News Article

'Soft' semiconductors could transform displays

News

Berkeley Lab researchers find tunable halide perovskites could usher in new generation of optoelectronic devices

Scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have shown that a class of compound semiconductor called halide perovskites is capable of emitting multiple, bright colours from a single nanowire at resolutions as small as 500 nanometers.

The findings, published online this week in the early edition of the Proceedings of the National Academy of Sciences, represent a challenge to quantum dot displays that rely upon traditional semiconductor nanocrystals to emit light. The researchers think it could also influence the development of new applications in optoelectronics, photovoltaics, nanoscopic lasers, and ultrasensitive photodetectors, among others.

The researchers used electron beam lithography to fabricate halide perovskite nanowire heterojunctions - a key building block of modern electronics and photovoltaics.

The researchers pointed out that the lattice in halide perovskites is held together by ionic instead of covalent bonds. In ionic bonds, atoms of opposite charges are attracted to each other and transfer electrons to each other. Covalent bonds, in contrast, occur when atoms share their electrons with each other.

"With inorganic halide perovskite, we can easily swap the anions in the ionic bonds while maintaining the single crystalline nature of the materials," said study principal investigator Peidong Yang, senior faculty scientist at Berkeley Lab's Materials Sciences Division. "This allows us to easily reconfigure the structure and composition of the material. That's why halide perovskites are considered soft lattice semiconductors. Covalent bonds, in contrast, are relatively robust and require more energy to change. Our study basically showed that we can pretty much change the composition of any segment of this soft semiconductor."

In this case, the researchers tested caesium lead halide perovskite, and then they used a common nanofabrication technique combined with anion exchange chemistry to swap out the halide ions to create cesium lead iodide, bromide, and chloride perovskites.

Each variation resulted in a different colour emitted. Moreover, the researchers showed that multiple heterojunctions could be engineered on a single nanowire. They were able to achieve a pixel size down to 500 nanometers, and they determined that the colour of the material was tunable throughout the entire range of visible light.

The researchers said that the chemical solution-processing technique used to treat this class of soft, ionic-bonded semiconductors is far simpler than methods used to manufacture traditional colloidal semiconductors.

"For conventional semiconductors, fabricating the junction is quite complicated and expensive," said study co-lead author Letian Dou, who conducted the work as a postdoctoral fellow in Yang's lab. "High temperatures and vacuum conditions are usually involved to control the materials' growth and doping. Precisely controlling the materials composition and property is also challenging because conventional semiconductors are 'hard' due to strong covalent bonding."

To swap the anions in a soft semiconductor, the material is soaked in a special chemical solution at room temperature.

"It's a simple process, and it is very easy to scale up," said Yang, who is also a professor of chemistry at UC Berkeley. "You don't need to spend long hours in a clean room, and you don't need high temperatures."

The researchers are continuing to improve the resolution of these soft semiconductors, and are working to integrate them into an electric circuit.

Other co-lead authors on this paper are Christopher Kley, UC Berkeley postdoctoral fellow, and Minliang Lai, UC Berkeley graduate student. Dou is now an assistant professor of chemical engineering at Purdue University.

Say hello to the heterogeneous revolution
Double heterostructure HEMTs for handsets
AlixLabs to collaborate with Linköping University
SiC MOSFETs: Understanding the benefits of plasma nitridation
Wolfspeed reports Q2 results
VueReal secures $40.5m to scale MicroSolid printing
Mitsubishi joins Horizon Europe's FLAGCHIP project
Vishay launches new high voltage SiC diodes
UK team leads diamond-FET breakthrough
GaN adoption at tipping point, says Infineon
BluGlass files tuneable GaN laser patents
QD company Quantum Science expands into new facility
Innoscience files lawsuit against Infineon
Riber revenues up 5% to €41.2m
Forvia Hella to use CoolSiC for next generation charging
Photon Design to exhibit QD simulation tool
Ortel transfers CW laser fabrication to Canada
Luminus adds red and blue multi-mode Lasers
PseudolithIC raises $6M for heterogeneous chiplet tech
Mesa sidewall design improves HV DUV LEDs
IQE revenue to exceed expectations
'Game-changing' VCSEL system targets clinical imaging
German start-up secures finance for SiC processing tech
Macom signs preliminaries for CHIPS Act funding
IQE and Quintessent partner on QD lasers for AI
EU funds perovskite tandems for fuel-free space propulsion
EU to invest €3m in GeSi quantum project
Transforming the current density of AlN Schottky barrier diodes
Turbocharging the GaN MOSFET with a HfO₂ gate
Wolfspeed launches Gen 4 SiC MOSFET technology
Report predicts high growth for UK's North East
Element Six unveils Cu-diamond composite
×
Search the news archive

To close this popup you can press escape or click the close icon.
Logo
x
Logo
×
Register - Step 1

You may choose to subscribe to the Compound Semiconductor Magazine, the Compound Semiconductor Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in: