Reduction of Phonon Escape Time for NbN Hot Electron Bolometers by Using GaN Buffer Layers
Artikel i vetenskaplig tidskrift, 2017

In this paper, we investigated the influence of the GaN buffer-layer on the phonon escape time of phonon-cooled hot electron bolometers based on NbN material and compared our findings to conventionally employed Si substrate. The presented experimental setup and operation of the HEB close to the critical temperature of the NbN film allowed for the extraction of phonon escape time in a simplified manner. Two independent experiments were performed at GARD/Chalmers and MSPU on a similar experimental setup at frequencies of approximately 180 and 140 GHz, respectively, and have shown reproducible and consistent results. By fitting the normalized IF measurement data to the heat balance equations, the escape time as fitting parameter has been deduced and amounts to 45 ps for the HEB based on Si substrate as in contrast to a significantly reduced escape time of 18 ps for the HEB utilizing the GaN buffer-layer under the assumption that no additional electron diffusion has taken place. This study indicates a high phonon transmissivity of the NbN-to-GaN interface and a prospective increase of IF bandwidth for HEB made of NbN on GaN buffer layers, which is desirable for future THz HEB heterodyne receivers.

ultra-thin film

HEB

NbN

IF bandwidth

GaN buffer-layer

Hot Electron Bolometer

Författare

Sascha Krause

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Vladislav Mityashkin

Moscow State Pedagogical University

Sergey Antipov

Moscow State Pedagogical University

Gregory Gol'tsman

Moscow State Pedagogical University

Denis Meledin

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Vincent Desmaris

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Victor Belitsky

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Mariusz Rudzinski

Instytutu Technologii Materialow Elektronicznych w Warszawie

IEEE Transactions on Terahertz Science and Technology

2156-342X (ISSN)

Vol. 7 53-59 7776966

Ämneskategorier

Nanoteknik

Annan elektroteknik och elektronik

Infrastruktur

Nanotekniklaboratoriet

DOI

10.1109/TTHZ.2016.2630845