Discipline: Technology and Engineering
Subcategory: Materials Science
Katy Gerace - Penn State University
Co-Author(s): Zakaria Y. Al Balushi and Joan M. Redwing, Penn State University, University Park, PA
From zero-dimensional quantum dots to three-dimensional bulk substrates, group-III nitrides semiconductors such as gallium nitride and indium nitride are considered one of the most important class of materials after silicon. This comes from their combined properties that are key enablers for the realization of disruptive technologies that are now truly ubiquitous and distributed: The efficient blue light-emitting diode (Nobel Prize in Physics 2014) for efficient white lighting, absorber materials for extraterrestrial application of solar cells, inverters for hybrid and electrical vehicles and a host of other potential applications that could be prime in shaping many next generation technologies. In order to do so, innovative research must be undertaken to extend the properties of group-III nitride semiconductors beyond what is currently possible. This ‘extension’ is realized by confining the material into a two-dimensional system that may lead to new untapped phenomena in condense matter physics, specifically when the thickness of the layer approaches a few atoms. As a result, one can expect massive changes in the electrical properties of the material, opening up new avenues of research in nanoscale devices and therefore establishing an entirely new platform that can complement or replace existing technology.
Here we investigate the conversion of few-layer nanosheets of indium selenide to indium nitride via a novel atom exchange technique that was first reported by Sreedhara et al. for the conversion of gallium selenide monolayers into gallium nitride1. In this study, samples are prepared by mechanical exfoliation onto a variety of host substrates, where the thickness of the exfoliated indium selenide flakes are characterized by atomic force microscopy and scanning electron microscopy and correlated with the optical properties as a function of the number of layers using Raman spectroscopy and photoluminescence. Samples are then exposed to ammonia gas at elevated temperatures, where the conversion process is monitored by ex situ characterization using advanced surface spectroscopic techniques that includes x-ray photoelectron and Auger spectroscopy. We also investigate the stability of the atomic layers before and after the conversion process in different environments, as the stability of these atomic layers directly impact the performance of electrical devices. Recognizing the impact of group-III nitride materials, it can be expected that the addition of two-dimensional atomic layers of indium nitride and related materials will open up new avenues of research in novel electronic and optoelectronic devices, such as miniaturized red emitter and high frequency devices for telecommunication.
References: M. B. Sreedhara; K. Vasu and C. N. R. Rao, Z. Anorg. Allg. Chem. 2014, 640, (14), 2737-2741.
Funder Acknowledgement(s): National Science Foundation
Faculty Advisor: Joan M. Redwing, firstname.lastname@example.org
Role: I characterized the indium selenide samples before and after ammonia exposure using a variety of structural and optical characterization methods.