Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Scientists discover new class of semiconducting entropy-stabilized materials

Crystal structure of GeSnPbSSeTe, a semiconducting entropy-stabilized chalcogenide alloy. The yellow atoms are cations (Ge, Sn, Pb) and the blue atoms are anions (S, Se, Te). The difference in lightness corresponds to different species of the anions and cations. The configurational entropy from the disorder of both the anion and the cation sublattices stabilizes the single-phase rocksalt solid solution, as demonstrated from first-principles calculations as well as experimental synthesis and characterization.

CREDIT
Logan Williams, Emmanouil Kioupakis, and Zihao Deng, Dept. of Materials Science & Engineering, University of Michigan
Crystal structure of GeSnPbSSeTe, a semiconducting entropy-stabilized chalcogenide alloy. The yellow atoms are cations (Ge, Sn, Pb) and the blue atoms are anions (S, Se, Te). The difference in lightness corresponds to different species of the anions and cations. The configurational entropy from the disorder of both the anion and the cation sublattices stabilizes the single-phase rocksalt solid solution, as demonstrated from first-principles calculations as well as experimental synthesis and characterization. CREDIT Logan Williams, Emmanouil Kioupakis, and Zihao Deng, Dept. of Materials Science & Engineering, University of Michigan

Abstract:
Semiconductors are important materials in numerous functional applications such as digital and analog electronics, solar cells, LEDs, and lasers. Semiconducting alloys are particularly useful for these applications since their properties can be engineered by tuning the mixing ratio or the alloy ingredients. However, the synthesis of multicomponent semiconductor alloys has been a big challenge due to thermodynamic phase segregation of the alloy into separate phases. Recently, University of Michigan researchers Emmanouil (Manos) Kioupakis and Pierre F. P. Poudeu, both in the Materials Science and Engineering Department, utilized entropy to stabilize a new class of semiconducting materials, based on GeSnPbSSeTe high-entropy chalcogenide alloys,[1] a discovery that paves the way for wider adoption of entropy-stabilized semiconductors in functional applications. Their article, "Semiconducting high-entropy chalcogenide alloys with ambi-ionic entropy stabilization and ambipolar doping" was recently published in the journal Chemistry of Materials.

Scientists discover new class of semiconducting entropy-stabilized materials

Ann Arbor, MI | Posted on July 31st, 2020

Entropy, a thermodynamic quantity that quantifies the degree of disorder in a material, has been exploited to synthesize a vast array of novel materials by mixing eachcomponent in an equimolar fashion, from high-entropy metallic alloys to entropy-stabilized ceramics. Despite having a large enthalpy of mixing, these materials can surprisingly crystalize in a single crystal structure, enabled by the large configurational entropy in the lattice. Kioupakis and Poudeu hypothesized that this principle of entropy stabilization can be applied to overcome the synthesis challenges of semiconducting alloys that prefer to segregation into thermodynamically more stable compounds. They tested their hypothesis on a 6-component II-VI chalcogenide alloy derived from the PbTe structure by mixing Ge, Sn, and Pb on the cation site, and S, Se, and Te on the anion site.

Using high throughput first-principles calculations, Kioupakis uncovered the complex interplay between the enthalpy and entropy in GeSnPbSSeTe high-entropy chalcogenide alloys. He found that the large configurational entropy from both anion and cation sublattices stabilizes the alloys into single-phase rocksalt solid solutions at the growth temperature. Despite being metastable at room temperature, these solid solutions can be preserved by fast cooling under ambient conditions. Poudeu later verified the theory predictions by synthesizing the e

quimolar composition (Ge1/3Sn1/3Pb1/3S1/3Se1/3Te1/3) by a two-step solid-state reaction followed by fast quenching in liquid nitrogen. The synthesized power showed well-defined XRD patterns corresponding to a pure rocksalt structure. Furthermore, they observed reversible phase transition between single-phase solid solution and multiple-phase segregation from DSC analysis and temperature dependent XRD, which is a key feature of entropy stabilization.

What makes high-entropy chalcogenide intriguing is their functional properties. Previously discovered high-entropy materials are either conducting metals or insulating ceramics, with a clear dearth in the semiconducting regime. Kioupakis and Poudeu found that. the equimolar GeSnPbSSeTe is an ambipolarly dopable semiconductor, with evidence from a calculated band gap of 0.86 eV and sign reversal of the measured Seebeck coefficient upon p-type doping with Na acceptors and n-type doping with Bi donors. The alloy also exhibits an ultralow thermal conductivity that is nearly independent of temperature. These fascinating functional properties make GeSnPbSSeTe a promising new material to be deployed in electronic, optoelectronic, photovoltaic, and thermoelectric devices.

Entropy stabilization is a general and powerful method to realize a vast array of materials compositions. The discovery of entropy stabilization in semiconducting chalcogenide alloys by the team at UM is only the tip of the iceberg that can pave the way for novel functional applications of entropy-stabilized materials.

###

This study was supported by the National Science Foundation through Grant No. DMR-1561008 (first-principles calculations, synthesis, and characterization) and the Department of Energy, Office of Basic Energy Sciences under Award # DE-SC-00018941 (electronic and thermal transport measurements). The DFT calculations used resources of the National Energy Research Scientific Computing (NERSC) Center, a DOE Office of Science User Facility supported under Contract No. DE-AC02-05CH11231.Related conference presentation:

Zihao Deng, Alan Olvera, Joseph Casamento, Juan Lopez, Logan Williams, Ruiming Lu, Guangsha Shi, Pierre F. P. Poudeu, and Emmanouil Kioupakis. Computational prediction and experimental discovery of semiconducting high-entropy chalcogenide alloys, MRS Fall Meeting 2019, EL04.01.05

####

For more information, please click here

Contacts:
Emmanouil (Manos) Kioupakis

734-945-4456

Copyright © University of Michigan

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Read the related publication:

Related News Press

News and information

New class of protein misfolding simulated in high definition: Evidence for recently identified and long-lasting type of protein misfolding bolstered by atomic-scale simulations and new experiments August 8th, 2025

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Lab to industry: InSe wafer-scale breakthrough for future electronics August 8th, 2025

Display technology/LEDs/SS Lighting/OLEDs

Development of 'transparent stretchable substrate' without image distortion could revolutionize next-generation displays Overcoming: Poisson's ratio enables fully transparent, distortion-free, non-deformable display substrates February 28th, 2025

Enhancing electron transfer for highly efficient upconversion: OLEDs Researchers elucidate the mechanisms of electron transfer in upconversion organic light-emitting diodes, resulting in improved efficiency August 16th, 2024

Efficient and stable hybrid perovskite-organic light-emitting diodes with external quantum efficiency exceeding 40 per cent July 5th, 2024

New organic molecule shatters phosphorescence efficiency records and paves way for rare metal-free applications July 5th, 2024

Govt.-Legislation/Regulation/Funding/Policy

New imaging approach transforms study of bacterial biofilms August 8th, 2025

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Possible Futures

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

New molecular technology targets tumors and simultaneously silences two ‘undruggable’ cancer genes August 8th, 2025

Simple algorithm paired with standard imaging tool could predict failure in lithium metal batteries August 8th, 2025

First real-time observation of two-dimensional melting process: Researchers at Mainz University unveil new insights into magnetic vortex structures August 8th, 2025

Chip Technology

Lab to industry: InSe wafer-scale breakthrough for future electronics August 8th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Programmable electron-induced color router array May 14th, 2025

Enhancing power factor of p- and n-type single-walled carbon nanotubes April 25th, 2025

Announcements

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Japan launches fully domestically produced quantum computer: Expo visitors to experience quantum computing firsthand August 8th, 2025

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

Photonics/Optics/Lasers

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Following the folds – with quantum technology: The connection between a crumpled sheet of paper and quantum technology: A research team at the EPFL in Lausanne (Switzerland) and the University of Konstanz (Germany) uses topology in microwave photonics to make improved systems of May 16th, 2025

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project