Silicon: quantum dot photovoltage triodes

Silicon is widespread in modern electronics, but its electronic bandgap prevents the detection of infrared radiation at wavelengths above 1,100 nanometers, which limits its applications in multiple fields such as night vision, health monitoring and space navigation systems. It is therefore of interest to integrate silicon with infrared-sensitive materials to broaden its detection wavelength. Here we demonstrate a photovoltage triode that can use silicon as the emitter but is also sensitive to infrared spectra owing to the heterointegrated quantum dot light absorber. The photovoltage generated at the quantum dot base region, attracting holes from silicon, leads to high responsivity (exceeding 410 A·W−1 with Vbias of −1.5 V), and a widely self-tunable spectral response. Our device has the maximal specific detectivity (4.73 × 1013 Jones with Vbias of −0.4 V) at 1,550 nm among the infrared sensitized silicon detectors, which opens a new path towards infrared and visible imaging in one chip with silicon technology compatibility.

Sun tracker sensor for attitude control of space navigation systems

We report a sun tracker sensor for attitude control of space navigation systems. The sensor exploits the concept of asynchronous operation previously devised by the authors for those devices. Asynchronous luminance sensors optimize sun trackers operation because only illuminated pixels are readout and can transmit data. This approach outperforms classic frame-based sun trackers in terms of bandwidth consumption, latency, and power consumption. The new sensor under study has been optimized for operation and interaction with other attitude control systems when it is embarked. The sensor power consumption is quite reduced. To save power, its pixels enter automatically in standby mode after gauging illumination levels. The device operates with only 0.45V. The pixel matrix has been devised to optionally be directly powered by energy harvesting systems based on photovoltaic diodes connected to a storage capacitor without a DC-DC converter.

Problem statement for practical modeling of temperature fields of gyroscopes in space navigation systems

The paper describes a method of studying temperature fields in fiber-optic gyroscopes that are part of complex navigation systems, using the example fiber-optic gyroscope as part of the angular velocity measurement system BIUS-M-1, developed by “Antares” (Saratov). The work relevance is due to the fact that currently existing methods for studying external and internal thermal effects on precision devices, and the resulting three-dimensional non-stationary temperature fields may be too complicated for practical application, or require significant computation and time resource. Also, not all contemporary models take into account such parameters, as low pressure and vacuum, the importance of which for devices operating in space orbital conditions cannot be underestimated. Therefore, modeling of the thermal process in various devices should be carried out at the design stage. At the same time, such modeling should not be labor-intensive, do not require large financial investment and computing resources. In this paper, the authors formulate a research problem, develop a thermal model, and present the main relations that are the components of the mathematical model of nonstationary three-dimensional inhomogeneous temperature fields in the fiber-optic gyroscope. The resulting model can be implemented quite simply in computational algorithms and software.

Improvement of the managing methodology of the development of complex agrotechnical systems of special purpose in modern conditions

Proper management of the agrobiological state of the soil environment is impossible without predicting the dynamics of changes in its condition. At the present stage, traditional monitoring systems based on laboratory analysis are most widely used. Such methods are quite accurate, but also cost-effective. Moreover, these systems have a rather large drawback – the speed of determining the agrobiological pa-rameters, in particular the nutrient content in the soil. All this ultimately affects the reliability and ef-fectiveness of decision making. However, even such information cannot provide the proper quality of technological operations in accordance with the agrobiological state of the soil environment. In this re-gard, there is an urgent need for the development and study of a methodology for managing the devel-opment of complex agrotechnical systems for special purposes in modern crop production technologies, the use of data that make it possible to ensure a given quality when performing a technological opera-tion. Based on the systematization of knowledge about managing the development of complex special-purpose systems, the features of their functioning in modern conditions, the directions of improving the management methodology, the principles of constructing a complex of methodological support for man-agement are determined, which implement closed cycles of developing control decisions and the organic relationship of long-term and current planning. As examples of complex special-purpose agrotechnical systems in this work, we use: agronomic (aerospace) monitoring systems for agricultural soils, precision farming systems using modern space navigation systems, and electrical conductivity monitoring sys-tems for agricultural soils.