Andreas Hemmetter
PhD student in graphene electronics,
avid traveler, and world federalist
Graphene-Based Microwave Circuits: A Review
Saeed, M., Palacios, P., Wei, M.-D., Baskent, E., Fan, C.-Y., Uzlu, B., Wang, K.-T., Hemmetter, A., Wang, Z., Neumaier, D., Lemme, M. C., Negra, R.,
Advanced Materials 2022, 2108473. https://doi.org/10.1002/adma.20210847
Over the past two decades, research on 2D materials has received much interest. Graphene is the most promising candidate regarding high-frequency applications thus far due to is high carrier mobility. Here, the research about the employment of graphene in micro- and millimeter-wave circuits is reviewed. The review starts with the different methodologies to grow and transfer graphene, before discussing the way graphene-based field-effect-transistors (GFETs) and diodes are built. A review on different approaches for realizing these devices is provided before discussing the employment of both GFETs and graphene diodes in different micro- and millimeter-wave circuits, showing the possibilities but also the limitations of this 2D material for high-frequency applications.
Terahertz Rectennas on Flexible Substrates Based on One-Dimensional Metal–Insulator–Graphene Diodes
Hemmetter, A., Yang, X., Wang, Z., Otto, M., Uzlu, B., Andree, M., Pfeiffer, U., Vorobiev, A., Stake, J., Lemme, M. C., Neumaier, D.,
ACS Applied Electronic Materials 2021, 3 (9), 3747-3753. https://pubs.acs.org/doi/full/10.1021/acsaelm.1c00134
Flexible energy harvesting devices fabricated in scalable thin-film processes are crucial for wearable electronics and the Internet of Things. We present a flexible rectenna based on a one-dimensional junction metal–insulator–graphene diode, offering low-noise power detection at terahertz (THz) frequencies. The rectennas are fabricated on a flexible polyimide film in a scalable process by photolithography using graphene grown by chemical vapor deposition. A one-dimensional junction reduces the junction capacitance and enables operation up to 170 GHz. The rectenna shows a maximum responsivity of 80 V/W at 167 GHz in free space measurements and minimum noise equivalent power of 80 pW/√Hz.
Graphene in 2D/3D Heterostructure Diodes for High Performance Electronics and Optoelectronics
Wang, Z., Hemmetter, A., Uzlu, B., Saeed, M., Hamed, A., Kataria, S., Negra, R., Neumaier, D., Lemme, M. C.,
Advanced Electronic Materials 2021, 7, 2001210. https://doi.org/10.1002/aelm.202001210
Diodes made of heterostructures of the 2D material graphene and conventional 3D materials are reviewed in this manuscript. Several applications in high frequency electronics and optoelectronics are highlighted. In particular, advantages of metal–insulator–graphene (MIG) diodes over conventional metal–insulator–metal diodes are discussed with respect to relevant figures-of-merit. The MIG concept is extended to 1D diodes. Several experimentally implemented radio frequency circuit applications with MIG diodes as active elements are presented. Furthermore, graphene-silicon Schottky diodes as well as MIG diodes are reviewed in terms of their potential for photodetection. Here, graphene-based diodes have the potential to outperform conventional photodetectors in several key figures-of-merit, such as overall responsivity or dark current levels. Obviously, advantages in some areas may come at the cost of disadvantages in others, so that 2D/3D diodes need to be tailored in application-specific ways.
Halide-Perovskite Resonant Nanophotonics
Makarov, S., Furasova, A., Tiguntseva, E., Hemmetter, A., Berestennikov, A., Pushkarev, A., Zakhidov, A., Kivshar, Y.,
Advanced Optical Materials 2019, 7, 1800784. https://doi.org/10.1002/adom.201800784
Halide perovskites have emerged recently as promising materials for many applications in photovoltaics and optoelectronics. Recent studies of optical properties of halide perovskites suggest many novel opportunities for a design of advanced nanophotonic devices due to their low-cost fabrication, relatively high values of the refractive index, existence of excitons at room temperatures, broadband bandgap tunability, high optical gain, and strong nonlinear response, as well as simplicity of their integration with other types of optical and electronic structures. This paper provides an overview of the recent progress in the study of optical effects originating from nanostructured perovskites, and it also oversees a range of potential applications of resonant nanophotonics with halide perovskites.
