Researchers in China, [J. Appl. Cryst. (2014). 47, 527-531] have found a convenient way to selectively prepare germanium sulfide nanostructures, including nanosheets and nanowires, that are more active than their bulk counterparts and could open the way to lower cost and safer optoelectronics, solar energy conversion and faster computer circuitry.
Germanium monosulfide, GeS, is emerging as one of the most important "IV–VI" semiconductor materials with potential in opto-electronics applications for telecommunications and computing, and as an absorber of light for use in solar energy conversion.
One important property is its much lower toxicity and environmental impact when compared to other semiconductors made with cadmium, lead and mercury.
It is less costly than other materials made with rare and noble metal elements. Indeed, glassy GeS has been used in lasers, fibre optic devices and infrared lenses as well as rewritable optical discs and non-volatile memory devices for several years. It is also used extensively as a solid electrolyte in conductive bridging random access memory (RAM) devices.
The repertoire of this material might be extended much further with the extra control that its use as nanostructured systems might allow. Liang Shi and Yumei Dai of the University of Science and Technology of China, in Hefei, point out that research in this area has lagged behind that with other IV-VI semiconductors.
They hope to change that and have focused on how nanosheets and nanowires of GeS might be readily formed. They have used X-ray powder diffraction, transmission electron microscopy, energy-dispersive X-ray spectrometry and scanning electron microscopy to investigate the structure, morphology, composition and optical absorption properties of their samples.
The team used simple "wet" chemistry to synthesis their products using germanium dichloride-dioxane complex, thiourea and oleylamine (OLA) as starting materials. The ingredients were mixed in a sealed reaction flask, blasted with ultrasound to exclude air and then stirred and heated.
The team was able to make nanosheets of GeS this way if the process was carried out for several hours at 593 Kelvin. At higher temperature, 613 Kelvin, they found that the sheets wind up into nanowires. Indeed, the precise heating time and temperature allowed them to control the structure of the final product. The team suggests that the rolling up of the nanosheets into nanowires is driven by the surface tension between the sheet and the OLA molecules during the heating.
Having proven the structural integrity of their GeS nanowires and nanosheets, the team built several test devices - a photoresponsive unit - which they used to evaluate the optical and electronic properties of the products. The team says that they have demonstrated "outstanding photoresponsive behaviour". This "indicates the potential use of as-synthesized GeS nanosheets and nanowires in solar energy conversion systems, such as the fabrication of photovoltaic devices".
For more information please contact
Dr Jonathan Agbenyega
Business Development Manager, IUCr
00 +44 (0) 1244 342878
About the IUCr
The IUCr is a scientific union adhering to the International Council for Science (ICSU). Its objectives are to promote international cooperation in crystallography and to contribute to all aspects of crystallography, to promote international publication of crystallographic research, to facilitate standardization of methods, units, nomenclatures and symbols, and to form a focus for the relations of crystallography to other sciences.
The IUCr fulfils these objectives by publishing in print and electronically primary scientific journals through Crystallography Journals Online, the series of reference volumes International Tables for Crystallography, distributing the quarterly IUCr Newsletter, maintaining the online World Directory/Database of Crystallographers, awarding the Ewald Prize and organising the triennial Congress and General Assembly.
Dr. Jonathan Agbenyega | EurekAlert!
Artificial Intelligence Helps in the Discovery of New Materials
21.09.2016 | Universität Basel
Magnetic polaron imaged for the first time
19.09.2016 | Aalto University
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.
Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...
At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.
In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...
Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.
K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...
23.09.2016 | Event News
20.09.2016 | Event News
16.09.2016 | Event News
23.09.2016 | Life Sciences
23.09.2016 | Health and Medicine
23.09.2016 | Life Sciences