High sensitivity black silicon photodetector and based-on-it spectrophotometer for real-time analysis of chemical and biological substances
Project Status: 3 Approved without Funding
Duration in months: 36 months
Objective
There is an increasing demand worldwide for low cost, fast, and reliable spectrophotometers for real-time monitoring chemical and biological substances in clinical chemistry, environmental sciences, and food related processes. A wide range of applications is foreseen in agriculture, veterinary analysis, food and drink industry, fermentation industry, waste water management, environment defense against pollutants and radiations, clinical diagnosis, drugs monitoring, mining, aerospace, mechanical production and many other fields.
Miniaturized field-deployable spectrophotometers require high-sensitivity and reliability photodetectors. Semiconductor photodetectors are mostly convenient for this purposes, but ones currently available have severe limitations since they can’t detect fixed wavelengths, lack tunability and also cannot perform synchronous scanning of the spectral radiation, which is required for a complete characterization of the spectral type.
During the last 10 years specific investigations on semiconductor photodetectors were conducted in the NPUA. In particular, participants of this Project develop the new physical principle and double-barrier semiconductor structure of photodetector that allows selecting and registering informative radiation coming from the object with a spectral accuracy of ? 1nm. This principle allows carrying out high accuracy spectral analysis of the informative radiation in the UV and visible regions. It allows, under longitudinal absorption of electromagnetic radiation, in the semiconductor structure, to observe the spatially separated absorption depths of different narrow ranges of informative waves, and to select their relative contribution in the summed photocurrent generated by integral flux of radiation. It will give a chance to selectively register the photosignal coming from the transmitter or the process under study. Preliminary results showed expediency and immediacy of continuation of such investigations.
The use of nanomaterials can enhance the photodetector efficiency at reduced cost and make photodetector technology more competitive with conventional technologies. In recent years, the participants of this Project have been actively working on research of principally new and exotic material – black silicon (in literature sometimes referred to as “silicon grass”). Black silicon results in near-unity absorption from the UV to the short wave infrared. It also exhibits large photoconductive gain at room temperature, with quantum efficiency greater than one. Our preliminary investigations revealed that the combination of black silicon nanostructures with standard semiconductor technology arises as a possible next step for achieving improved photodetectors characteristics. Black silicon's unique physical parameters will revolutionize photonic device architecture.
The participants of this Project from IMNE have great experience and skills, as well as modern technological opportunities in the fields of design, processing, testing and packaging of nanoscale semiconductor structures intended for short and medium waves infrared photodetector technologies.
The present Project is based and considered logical continuation of our achieved scientific investigations. It addresses the development of fundamentally new photodetector and based-on-it spectrophotometer useable for real-time analysis of chemical and biological substances. In order to achieve these objectives, work plan for the Project is divided into five technical work packages (WP):
I. Design and Specification. At the start of the Project, the participants will specify target photodetectors and spectrophotometers, detection limits and test conditions relevant to end users. Specification of the common testing and benchmarking procedures, operating protocols, network architectures and communications protocols will also be carried out.
II. Materials Development and Characterization. A variety of novel nanostructured semiconductor materials will be developed and characterized with respect to their opto-electrical and electro-physical properties. A special attention will be paid to investigation of black silicon. This material will be tested both as antireflection coating and photosensitive layer, as well as back side textured surface for photodetectors.
III. Photodetector Development. Development of the black silicon photodetector structures will be carried out for initial testing and characterization. The work will be carried out as follows:
· To carry out the experimental study of the spectral selective sensitivity of the photodetector structures and of the capabilities of the spectral analysis considering the peculiarities of the distribution of spectral waves, the electrical field and the radiation flux density in it.
· To develop a complete algorithm and the relevant program that would include all the possible cause-effect relations of the interaction of the electromagnetic radiation with the object under study.
IV. Spectrophotometer Development. The respective circuit solutions between the photodetector and the remaining elements (controller, display, battery) of the spectrophotometer will be developed. Spectral range of sensitivity, the resolution, and the possibilities of the spectrophotometer will be determined.
V. Integration, Testing and Industrial Validation. The final WP focuses on the integration of the spectrophotometer modules and quantitative testing and validation of the performance of the modules. The common network platform for control and communication of the sensor modules will be developed. Driver software for control and read-out from different sensor types will be done at different sites prior to integration with the network and the chemometric “learning” algorithms. The final testing and assessment will be carried out in a “real-world” proving ground.
Collaboration with foreign scientists and specialists for joint modification, testing and demonstration of our technology, as well as design of final product (spectrophotometer) will be very useful for us. Foreign collaborators may participate in fabrication of black silicon nanostructures, as well as in the investigation of the electrical and other sensorial properties of these structures. The role of foreign collaborators is also to discuss the problems and to exchange information, obtained during the implementation process of the Project, to take part in scientific seminars and conferences, organized by the executor. They may also assist the commercialization of the obtained results and their advance to the market.
The Project proposed fully meets the ISTC goals and promotes them to be realized.
The Project will result in new scientific results and technical patent will be filed. Scientific results will be disseminated through the publications in scientific peer-reviewed journals and presentations in international conferences.
The Project is absolutely original in its tasks and methods to achieve them with no interference with any existing activities of other research teams.
To reach these objectives, many of the features of opto- & micro- & nanoelectronics, IT and mathematical modelling have to be revisited. From this point of view, the experience and skills of the participants of the Project are well complemented by each other, enhancing the probability of success with the Project objectives.
