Mariusz Duk

Technology and characterization of 4H-SiC p-i-n junctions

Silicon Carbide (SiC) photodiodes have been proposed in recent years for ultraviolet (UV) light detection because of their robustness even in harsh environments, high quantum efficiency in all the UV range (200nm-400nm), excellent visible and infra-red blindness excluding UV filters implementation, low dark current and high speed. 4H-SiC has a bandgap three times larger (3.26eV) than Si and, thus, SiC detectors should have much higher sensitivity than Si detectors. In this paper, we present an overview of results on 4H-SiC p-i-n junctions fabrication and characterization. We used implantation technique to obtain p-region of the investigated structure. The ohmic contacts were formed using evaporation, etching and lift-off. Current-voltage, contact resistance and electroluminescence are the main characteristics of the presented devices. All the diodes showed excellent rectification with leakage current density of less than 10-9A/cm2.

Automatic detection of characteristic points and form of optical signals in multiparametric capillary sensors

The time series sequence of data readings are the input for computer aided analysis of signal from the multiparametric optical capillary sensor. The time series signals have characteristic points and forms. Their analysis by trained human operators is time consuming and sometimes lacks of precision because of the presence of signal noise. The noises can be mostly rejected with advanced electronic signal processing, but the output analog signal is often modified by the electromagnetic environment and by the noise generated by electronic elements. We propose and analyze an algorithm that can be used as an automatic detector of characteristic points and form of the time series signals that are produced by the measuring head and the analog electronic units of the biodiesel fuel quality test sensor.

Large-area transparent in visible range silicon carbide photodiode

This paper describes the construction, fabrication and properties of large-area ultra violet detector that is transparent in the visible range. The device was made on n-type 4H SiC substrate with a double epitaxial layer in which aluminum was implanted to form a p-n junction close to the surface, and a SiO2 layer was formed for passivation, without a guard ring. The design of the top and bottom electrodes of 4mm diameter UV sensitive area allows not less than 20% visible range transmission. This transmission was measured across sensitive area of examined devices and was only 5% lower than that of the substrate before implantation and electrodes deposition.

Intelligent Photonic Sensors for Application in Decentralized Wastewater Systems

Michal Borecki1, Michael L. Korwin-Pawlowski2, Maria Beblowska1, Jan Szmidt1, Maciej Szmidt3, Mariusz Duk4, Kaja Urbanska3 and Andrzej Jakubowski1 1Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, 2Departement d’informatique et d’ingenierie, Universite du Quebec en Outaouais, 3Warsaw University of Life Sciences, 4Lublin University of Technology, 1,3,4Poland 2Canada

Application of flame monitoring system for flame spectrum analysis in industrial conditions

The flame monitoring system is intended to use in industrial condition for controlling pulverized coal combustion in power boiler. Placing the fiber-optic probes close to the each burner, one can obtain detailed information of the coal combustion process within the single burner. In order to enhance flame-monitoring system sensitivity for detection of fuels composition changes, we have measured flame emission spectra.

Innovative SiC over Si photodiode based dual-band, 3D integrated detector

This paper describes the fabrication of 3D-stacked, dual-band sensitive device and their preliminary characterization results. The device consists of two 3D integrated detectors. The square chip with fabricated 4H-SiC p-i-n junction was mounted on commercial silicon chip with large area VIS-photodiode made by Institute of Electron Technology in Warsaw. The UV-photodetector was made on n-type 4H-SiC substrate with a double epitaxial layer in which aluminum was implanted to form a p-n junction close to the surface, and a silicon dioxide layer was formed for passivation, without a guard ring. The optical and electrical characterization of each of the photodiode structures has been discussed including dark current and spectral response measurements of large-area silicon diode with 4H-SiC p-i-n junction. All the diodes showed excellent rectification with low leakage current.

Fabrication and characterization of epitaxial 4H-SiC pn junctions

This paper provides an overview of the process of 4H-SiC pn junction fabrication and characterization. The samples used in this study were fabricated in a resistively heated horizontal hot-wall Chemical Vapor Deposition reactor. The homo-epitaxial layers were grown on commercially available 4H-SiC substrates (Cree). In order to obtain p-type epilayers, they were intentionally doped with aluminum. In this work, we present our recently developed 4H-SiC pn junctions fabrication and characterization results. The ohmic contacts were formed using evaporation, etching, lift-off and high temperature annealing. Current-voltage characteristics of the devices were demonstrated.

Analysis of two dimensional signals via curvelet transform

This paper describes an application of curvelet transform analysis problem of interferometric images. Comparing to two-dimensional wavelet transform, curvelet transform has higher time-frequency resolution. This article includes numerical experiments, which were executed on random interferometric image. In the result of nonlinear approximations, curvelet transform obtains matrix with smaller number of coefficients than is guaranteed by wavelet transform. Additionally, denoising simulations show that curvelet could be a very good tool to remove noise from images.

Passive optical gas concentration sensor in industrial boilers

This paper presents review of optical radiation measurement method in combustion process. Analysis and comparison of different methods is described and some applications in coal combustion boilers are shown. Such sensors can detect presence of target molecule, measure concentration ratio of two molecules and quantitatively measure the concentration.

Information measuring systems with mobile devices for identification of air pollution parameters caused by transport

The analysis of modern information measuring systems (IMS) for identification model parameters of the air pollution is carried out. That allows to increase the accuracy of this identification due to their complex application. The known model based on the fuzzy knowledge base was adapted to this task. It is specified how the offered IMS can increase the accuracy of the parameters identification. The results of the experiment with the use of the offered IMS in Vinnytsia city presented in the paper.