Nanocrystal-based microcavity light-emitting devices operating in the telecommunication wavelength range

Abstract

Highly luminescent colloidally prepared HgTe nanocrystals (NCs) are used to fabricate microcavity light-emitting devices operating around 1.5μm. They consist of a Bragg interference mirror from standard optical materials deposited on glass substrates, an active layer embedding the nanocrystals, and a metallic top mirror. These devices give highly directional narrow single-mode emission with a beam divergence below 3° and a spectral width smaller by a factor of 8 than that of a NC reference sample. The emission wavelength can be tuned between 1.4 and 1.75μm by changing the cavity length and thus, the cavity finesse. The influence of the latter on output power and beam divergence is discussed. Furthermore, operation up to 75 °C is demonstrated without degradation of the NCs, which is promising for potential applications.

Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

“…HgTe nanocrystals (NCs) emit photoluminescence (PL) and electroluminescence (EL); hence, they are used to gain light in the near-infrared (Roither et al 2005; Shopova et al 2004). The PL and EL devices are based on quantum effects, which take place when the radius of the NC is reduced below the Bohr exciton radius, which is r  = 40 nm in bulk HgTe (Rath 2005).…”

Colloidal Tm3+/Yb3+‐Doped LiYF4 Nanocrystals: Multiple Luminescence Spanning the UV to NIR Regions via Low‐Energy Excitation

“…The second appealing result is the Stokes emission at $1.46 mm from the dispersible Tm 3þ /Yb 3þ -doped LiYF 4 nanocrystals, which may be interesting for optical amplifications of telecommunication signals, as this region falls in the important optical telecommunication S-band (1460-1530 nm). [19][20][21] It should be noted that while the energy of this transition is lower than the incident laser energy, the emitting 3 H 4 state is populated via a two-photon process ( Fig. S3, Supporting Information).…”

Quantum confinement in layer-by-layer deposited colloidal HgTe nanocrystals determined by spectroscopic ellipsometry

“…We have fabricated five different sizes of NCs by using growth times of 0, 90, 150, 300 and 600 min, which corresponds to approximate NC diameters of 3.5 nm, which we name ''smallest'', 4.1, 5.3, 6.9 and 10.7 nm, which we name ''largest''. With these NCs, thin mono-and multi-layer films were self-assembled using a layer-by-layer deposition technique driven by electrostatic interaction [1,9] utilizing poly(-diallyldimethyl-ammonium chloride) (PDDA) and TGstabilized HgTe NCs as positively and negatively charged species, respectively. Alternative adsorption of each component from its diluted aqueous solutions resulted in the formation of a sequence of (PDDA/HgTe NCs) bilayers.…”

“…Mercury telluride (HgTe) in its bulk form is an inverted band gap semiconductor at room temperature (E g = À0.15 eV) which allows the fabrication of NCs with a small energy gap for efficient light emitters in the infrared. The development of devices based on photoluminescence and electroluminescence using HgTe NCs has been reported [1,2].…”