Researchers Discover Promising Nitride Semiconductor for Optoelectronics
June 24, 2016 | Tokyo Institute of TechnologyEstimated reading time: 3 minutes
Researchers use simulations to identify previously undiscovered semiconductors with promising attributes for optical and electronic applications. A nitride among those proposed has been successfully fabricated using high-pressure synthesis and is found to emit red light.
The discovery of new semiconducting materials is a scientifically and technologically important issue; state researchers in Japan in a recent report. Increasingly sophisticated electronic devices, such as smartphones and laptops, are raising demand for semiconductors with wider ranges of properties. Now Fumiyasu Oba and colleagues at Tokyo Institute of Technology and Kyoto University have used calculations to screen a set of compounds for potential semiconductor candidates. The study identified 11 previously unreported materials, including the particularly promising compound calcium zinc nitride (CaZn2N2).
The researchers limit their study to nitrides because they tend to be chemically stable and can be readily made with existing techniques. Nitrogen is also a widely abundant and environmentally friendly element, but, at present, the nitrides used in industry are largely limited to gallium and indium compounds. Based on similarities in the electronic structure, the researchers rationalised that ternary zinc nitrides would be promising compounds to consider for new semiconductors in this field.
The researchers highlight the previously unreported semiconductor CaZn2N2, which should have a high electrical conductivity and a strong interaction with light. These properties are indicators of good performance in optoelectronic applications such as light emitting diodes (LEDs) and solar cells. It is also made entirely of earth-abundant elements and so can be relatively cheap to make.
Synthesis of the material using high-pressure techniques confirmed the hypothesised properties and also revealed red luminescence even at room temperature; thereby validating the study's approach. The paper also shows that other earth-abundant materials, such as calcium magnesium nitride, can be used to tune the electrical properties of CaZn2N2, further increasing the eligibility of this material for use in devices.
As Oba and colleagues conclude, "The present study demonstrates accelerated materials discovery via cutting-edge computational screening followed by targeted experiments."
Background
Limitations of existing semiconductors
Silicon and, to a lesser degree, germanium are the foundations of almost all electronic devices that govern modern life. However, these materials are not suited for optoelectronic applications, such as LEDs for TV or mobile phone screens. Here, the materials gallium nitride (GaN) and indium nitride (InN) dominate currently, but the discovery of new nitrides could pave the way to new applications.
Foremost among the characteristics Oba and colleagues sought in any new compound was high conductivity, which is crucial for most semiconductor applications. GaN and InN have spatially diffuse orbital characteristics, which result in the high electrical conductivity that has led to their success. The researchers considered materials with such properties similar to GaN and InN in order to find new industry-relevant semiconductors. Zinc nitride has these desirable properties but is difficult to make. As a result, the researchers decided to screen for ternary compounds comprising zinc, nitrogen and a third element. This approach led to the identification of 11 new materials, including the exciting CaZn2N2.
Earth abundant elements
Rare elements can confer many useful properties in semiconductor compounds but they are increasingly difficult to extract and their processing costs can be very expensive. As a result, there is an increasing interest in earth-abundant materials that may be used as alternatives. By using nitrogen and zinc components as criteria for their screening methods, Oba and colleagues are able to maximize the chances of cost competitiveness for their discoveries compared to known materials.
Calcium zinc nitride
CaZn2N2 has not been reported previously but was identified by the researchers using their materials discovery computational approach. They were also able to predict the correct synthesis conditions for CaZn2N2, leading to the successful formation of the new compound using high-pressure synthesis. Further experiments confirmed that the compound has a direct bandgap and favourable optical properties.
Suggested Items
SMC Korea 2024 to Highlight Semiconductor Materials Trends and Innovations on Industry’s Path to $1 Trillion
04/24/2024 | SEMIWith Korea a major consumer of semiconductor materials and advanced materials a key driver of innovation on the industry’s path to $1 trillion, industry leaders and experts will gather at SMC (Strategic Materials Conference) Korea 2024 on May 29 at the Suwon Convention Center in Gyeonggi-do, South Korea to provide insights into the latest materials developments and trends. Registration is open.
Groundbreaking Ceremony Marks the Beginning of a New Era for Newccess Industrial; The Construction of the MINGXIN Building
04/12/2024 | Newccess IndustrialOn a clear and sunny day in March, the groundbreaking ceremony for the MINGXIN Building took place in Shenzhen, China. This moment marked the official commencement of construction for a project that will reshape the semiconductor materials industry.
The Need for a Holistic Global Sustainability Standard
04/10/2024 | Michael Ford, Aegis SoftwareNo one can deny that the resources of our fragile planet are finite. The environment seems like a third party, subject to constant degradation. We’re acutely aware of the effects of pollution on our climate, and despite our “throw-away” culture, recycling and recovery of materials has remained relatively expensive, even as we use more energy just to survive.
iNEMI Publishes Four Roadmap Topics
04/04/2024 | iNEMIThe International Electronics Manufacturing Initiative (iNEMI) announces the availability of the first roadmap topics in the new iNEMI Roadmap format. Printed circuit boards, sustainable electronics, smart manufacturing, and mmWave materials and test are now available online.
Insulectro’s 'Storekeepers' Extend Their Welcome to Technology Village at IPC APEX EXPO
04/03/2024 | InsulectroInsulectro, the largest distributor of materials for use in the manufacture of PCBs and printed electronics, welcomes attendees to its TECHNOLOGY VILLAGE during this year’s IPC APEX EXPO at the Anaheim Convention Center, April 9-11, 2024.