An IR modulator based on the self-assembly of gold nanoparticles on germanium

Abstract

By using a polyelectrolyte layer gold nanoparticles have been assembled onto a Ge internal reflection element. Upon illumination with visible and near infrared light strong infrared absorption has been observed, which can be traced to intervalence band transitions in Ge. This reveals the existence of holes in the Ge near its valence band edge. The switching between light and dark states is faster than 160 μs and the device acts as an infrared modulator. The effect develops with a peculiar kinetics, which may indicate the development of an interfacial layer between germanium and gold that allows efficient electron transfer upon illumination.

Characterization of Salophen Co(III) Acetate Ionophore for Nitrite Recognition

“…The solutions were passed through the cell and over the ZnSe crystal at a flow rate of 0.1 mL min À1 by means of a peristaltic pump (Ismatec, Reglo 100) located in front of the cell. All experiments were performed at room temperature and the spectrometer was evacuated to avoid contributions from gas-phase water and CO 2 [20].…”

Mapping Infrared Enhancement around Gold Nanoparticles Using Polyelectrolytes

“…We recently reported the preparation using the layer-by-layer (LBL) approach and optical properties of polyelectrolyte–metal nanoparticle composite films grown on glass slides and on Ge crystals used for attenuated total reflection infrared (ATR-IR) spectroscopy. − LBL deposition of polyelectrolytes is a versatile technique with possible application in biomedicine, solar cells, drug delivery, and light-emitting diodes . The environment friendly, aqueous solution-based technique can be used to incorporate charged particles such as metal nanoparticles into multilayer systems .…”

Ultrafast synthesis of continuous Au thin films from chloroauric acid solution using an atmospheric pressure plasma jet

“…Gold (Au) nanoparticles and thin lms have been extensively used in sensors, catalysts, infrared devices, and plasmonic devices. [1][2][3] Electronics grade Au thin lms are frequently prepared by vacuum deposition methods. One alternative method to deposit Au is using a non-vacuum solution process via the reduction of chloroauric acid (HAuCl 4 ).…”