Justyna Mech

Arithmetic Device Based on Multiple Schottky-like Junctions

Photoelectrodes containing cadmium sulfide deposited as powders and crystalline thin layers combined with semi-solid ionic liquid electrolyte behave like Schottky photodiodes. Appropriate connection of these devices results in simple optoelectronic logic gates (AND, XOR) and enables construction of an optoelectronic binary half-adder.

Photoelectrochemistry of n-type antimony sulfoiodide nanowires

In the presented work the photoelectrochemical properties of SbSI along with the electronic structure (i.e. conduction and valence band edge potentials as well as conductivity type) of sonochemically obtained nanowires are discussed for the first time. The spectroscopic investigations indicate interesting optical properties, including surface isotope effect and excitonic emission. The photoelectrochemical investigation of SbSI revealed the occurrence of the photoelectrochemical photocurrent switching effect. It may be defined as a change in photocurrent direction (generated at the illuminated semiconducting electrode immersed in electrolyte) due to an appropriate polarization of the electrode versus the reference electrode. It is often observed for semiconductors as a result of the reduction of molecular oxygen dissolved in the electrolyte. However, in the case of SbSI, the photocurrent switching was recorded regardless of the presence of molecular oxygen in the electrolyte, probably due to the reduction of triiodide species formed at anodic polarization of the SbSI electrode, in an iodide-containing electrolyte. The switching potential (i.e. the potential where anodic-to-cathodic photocurrent transition occurs) equals to ca. 0.4 V versus standard hydrogen electrode, which is close to the formal potential of the I(-)/I3(-) redox couple. Therefore, this semiconducting material is of potential interest for the construction of new photovoltaic systems, novel optoelectronic switches and logic devices.

Electrochemically deposited nanocrystalline InSb thin films and their electrical properties

We present an electrochemical route to prepare nanocrystalline InSb thin films that can be transferred to an industrial scale. The morphology, composition, and crystallinity of the prepared uniform and compact thin films with a surface area of around 1 cm2 were investigated. The essential electrical characteristics such as conductivity, Seebeck coefficient, the type, concentration and mobility of charge carriers have been examined and compared with InSb nanowires obtained in the same system for electrochemical deposition (fixed pulse sequence, temperature, electrolyte composition, and system geometry). Moreover, obtained thin films show much higher band gap energy (0.53 eV) compared to the bulk material (0.17 eV) and InSb nanowires (0.195 eV).

TiO2–anthraquinone hybrids: from quantum-chemical design to functional materials

A series of materials based on titanium dioxide nanoparticles and anthraquinone dyes have been modelled using the quantum mechanical minimalistic model. Based on the computational results some spectral and photoelectrochemical properties of these materials have been predicted. Experimental studies indicate that the quantum-chemical predictions are correct. New materials exhibit interesting switching properties and moderate photosensitization towards visible light. Furthermore, based on excited state properties of dye–semiconductor hybrids diverse photocatalytic properties, including the activation of molecular oxygen, can be predicted.

Acoustic wave sensing devices and their LTCC packaging

The paper presents the relevant results of manufacturing LTCC packages intended for chip assembly as well as the RF behavior of SAW and FBAR structures used as temperature and, respectively, humidity sensing devices. Packaged SAW-based temperature sensors were characterized in a cryostat set-up, while the packaged FBAR-based humidity sensors were measured in a small enclosure with controlled humidity. Linear behaviour of the frequency shift vs. temperature and, respectively, relative humidity was evidenced.