REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

PHOTON MANAGEMENT IN SEMICONDUCTOR INFRARED PHOTODETECTORS: DIFFRACTIVE AND PLASMONIC ANTIREFLECTIVE STRUCTURES

ZORAN JAKŠIĆ,
MILIJA SARAJLIĆ,
KATARINA RADULOVIĆ,
MARKO OBRADOV,
DRAGAN TANASKOVIĆ,
SLOBODAN VUKOVIĆ

Centre of Microelectronic Technologies and Single Crystals, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Belgrade, Serbia, jaksa@nanosys.ihtm.bg.ac.rs

Abstract: Due to their high specific detectivities and large response speeds, photodetectors based on narrow-bandgap semiconductors like indium antimonide and mercury cadmium telluride are indispensable for mid- and far-infrared wavelength ranges. Their response is directly proportional to the infrared radiation flux introduced to the detector active area. Thus various photon management techniques are of crucial importance for enhancing their performance. This work analyzes the use of subwavelength nanophotonic structures with antireflective properties. It considers surface-based diffractive optical structure that can be produced by micromachining and nanofabrication. The first part of the consideration is dedicated to all-dielectric subwavelength arrays with 1D and 2D periodicity, which effectively behave as impedance-matching structures with graded effective refractive index. The consideration is then expanded to metal-dielectric structures, especially those belonging to the class of the so-called plasmonic ultra-absorbers. Technologies available in Serbia are then investigated technologies for the fabrication of the dielectric and metal-dielectric subwavelength antireflective structures for the infrared, including isotropic and anisotropic etching of surface reliefs and ultrathin-film deposition techniques. It is concluded that diffractive dielectric and plasmonic structures offer a novel degree of freedom in optimization of infrared semiconductor photodetectors.

Key words: Infrared Photodetectors, Photon Management, Night Vision, Plasmonics, Diffractive Optical Elements.