Abstract-SU-8 based planar metamaterials with fourfold symmetry as selective terahertz absorbers

B. Grześkiewicz,  A. Sierakowski, J. Marczewski, N. Pałka,  E .Wolarz,

https://www.sciencedirect.com/science/article/abs/pii/S1230340218300532

We report on the absorption properties of polarization-insensitive transmissive and reflective metamaterial absorbers based on two planar aluminium periodic structures and SU-8 epoxy resist. These absorbers were investigated using numerical simulation and experimental methods in the terahertz range (below 2 THz). SU-8 is a very promising organic material for dielectric layers in planar metamaterials, because its application simplifies the process of fabricating these structures and significantly reduces the fabrication time. The experimental absorption of the metamaterial absorbers has narrowband characteristics that were consistent with the numerical simulations. Power flow analysis in the transmissive metamaterial unit cell shows that the absorption in the terahertz range occurs primarily in the SU-8 layer of the absorber.

Abstract-Silicon junctionless field effect transistors as room temperature terahertz detectors

J. Marczewski^1,a), W. Knap^2,3, D. Tomaszewski¹, M. Zaborowski¹ and P. Zagrajek⁴
 HIDE AFFILIATIONS
1 Institute of Electron Technology, al. Lotnikow 32/46, 02-668 Warsaw, Poland
2 Institute of High Pressure Physics of the Polish Academy of Sciences, ul. Sokolowska 29/37, 01-142 Warsaw, Poland
3 Laboratory Charles Coulomb, Montpellier University & CNRS, Place E. Bataillon, Montpellier 34095, France
4 Institute of Optoelectronics, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
a) Author to whom correspondence should be addressed. Electronic mail: jmarcz@ite.waw.pl
J. Appl. Phys. 118, 104502 (2015); http://dx.doi.org/10.1063/1.4929967
http://scitation.aip.org/content/aip/journal/jap/118/10/10.1063/1.4929967

Terahertz (THz) radiation detection by junctionless metal-oxide-semiconductor field-effect transistors (JL MOSFETs) was studied and compared with THz detection using conventionalMOSFETs. It has been shown that in contrast to the behavior of standard transistors, the junctionless devices have a significant responsivity also in the open channel (low resistance) state. The responsivity for a photolithographically defined JL FET was 70 V/W and the noise equivalent power 460 pW/√Hz. Working in the open channel state may be advantageous for THz wireless and imaging applications because of its low thermal noise and possible high operating speed or large bandwidth. It has been proven that the junctionless MOSFETs can also operate in a zero gate bias mode, which enables simplification of the THz array circuitry. Existing models of THz detection by MOSFETs were considered and it has been demonstrated that the process of detection by these junctionless devices cannot be explained within the framework of the commonly accepted models and therefore requires a new theoretical approach.