The Waterloo Institute for Nanotechnology (WIN) has launched a new seminar series, Quantum Nano Collision (QNC) Seminar Series, to deepen the engagement of the Waterloo researchers who work at the interface of quantum and nanotechnologies. This seminar series will also provide opportunities for senior graduate students, post-doctoral fellows, and research associates to present their innovative work along with the faculty members to bring together the excitement around these cutting-edge technologies that would shape our future.
The next talk for the QNC Seminar Series will be delivered by Professor Kevin Musselman.
Registration is required. If you have any questions or issues registering, please contact firstname.lastname@example.org
Nanomaterial-driven improvements in quantum-tunneling metal-insulator-metal diodes
Quantum-tunneling metal-insulator-metal (MIM) diodes are capable of rectifying high-frequency (e.g., terahertz) current, since their operation is based on ultra-fast quantum tunneling through an insulator layer. These diodes are promising for applications in energy harvesting, infrared detection, and wireless power transmission, among others; however, the manufacturability and performance of these diodes require improvement. We have used atmospheric-pressure spatial atomic layer deposition (AP-SALD), an open-air, scalable, high-throughput version of atomic layer deposition, to fabricate ultrathin insulating films for quantum-tunneling MIM diodes. The MIM diodes fabricated by AP-SALD showed better performance than equivalent diodes where the insulator was fabricated by conventional plasma-enhanced atomic layer deposition. We also used our AP-SALD system to develop a method to rapidly deposit thin films with nanoscale thickness gradients in open air, which enabled combinatorial high-throughput (CHT) optimization of an MIM diode. We fabricated 360 Pt/Al2O3/Al MIM diodes with 18 different Al2O3 thicknesses ranging from 2.5 nm to 10 nm on a single wafer and identified an optimal insulator thickness of 6.5 to 7.0 nm. Despite this optimization, the performance of our diodes remained modest. In fact, quantum-tunneling MIM diodes with zero-bias responsivities greater than those of traditional Schottky diodes had not been demonstrated, even though they are not restricted by the thermal voltage limit of Schottky diodes. Our group then used defect engineering of multiple insulator layers to induce asymmetric and defect-mediated conduction mechanisms into the diodes, resulting in significant performance enhancements. Zero-bias responsivities as high as 36.8 A/W were obtained. These surpassed the 19.4 A/W theoretical limit for Schottky diodes for the first time and are more than double those previously reported for MIM diodes.
Kevin Musselman joined the University of Waterloo in 2015, where his research focuses on the development of functional nanomaterials for a variety of devices and applications, including photovoltaic solar cells, LEDs, high-frequency diodes, resistive memory, cancer theranostics, and novel sensors.
Musselman has developed atmospheric pressure spatial atomic layer deposition (AP-SALD) technology, including the construction of the first AP-SALD systems in Canada, and has helped pioneer the integration of AP-SALD thin films in (opto)electronic devices, including solar cells, LEDs, quantum-tunneling metal-insulator-metal diodes, and memristive devices. With Waterloo collaborators, he has also developed ultrafast laser processing techniques for the fabrication of novel 2D nanoparticles.