Kumar S.,Ultrasolar technology |
Sharma N.C.,Ultrasolar technology |
Saha S.,Santa Clara University
Nanoscience and Nanotechnology Letters | Year: 2016
This paper presents a method to enhance the efficiency of silicon photovoltaic (Si PV) cells by creating metastable high energy states in the conduction band of silicon with high frequency electric fields and a theoretical model to predict the appearance of the metastable energy states. The states are generated by the interaction of the oscillating electric field from the high frequency electric pulses with the electrostatic potential equilibrium in the lattice. Dramatic increase in the output energy of c-Si PV cells has been observed upon application of extremely high frequency (>50 GHz) electric pulses. Analysis of absorption spectroscopy shows the appearance of multiple additional absorption peaks in visible as well as high energy region (<400 nm) of the solar spectrum. It is concluded that the additional energy generated comes from capturing of hot carriers which are the electrons and holes generated when the PV cell absorbs photons with energy above the bottom of conduction band. These carriers (electrons and holes) lose their energy by the process of thermalization within a few picoseconds. It appears that the interaction of high frequency electric pulses with silicon lattice enables the lattice to delay the thermalization to >200 μs (similar to minority carrier life time) and enables the electrode to capture these hot carriers before the energy is lost by thermalization. Pulses used to generate the states are produced using a special nanostructure involving perovskite based pyroelectric material. Copyright © 2016 American Scientific Publishers All rights reserved.
Dutta A.,Jadavpur University |
Koley K.,Jadavpur University |
Saha S.K.,Ultrasolar technology |
Sarkar C.K.,Jadavpur University
IEEE Transactions on Electron Devices | Year: 2014
In this paper, the harmonic distortion (HD) in the underlap double-gate MOSFETs (UDG-MOSFETs) with high-k spacers is analyzed. The HD occurs due to the nonlinearity in the device performance and therefore, a detailed analysis of the HD as a function of spacer dielectric constant (k) is critical to ensure device reliability for RF performance. In this paper, the analysis is performed for the primary components, the second-order distortion (HD2), and the third-order distortion (HD3) along with the total HD. The parameters analyzed for the HD study of the UDG-MOSFETs with high-k spacers are the drain current, the transconductance, and the transconductance generation factor. The results of the analysis suggest a reduction in the distortion phenomenon for the high-k spacer devices, thereby ensuring reliability of these devices for RF applications. Also, a detailed analysis of HD2 and HD3 as a function of k of the high-k spacers are performed using UDG-MOSFETs in cascode and differential amplifier circuits. © 1963-2012 IEEE.
Ghosh S.,Jadavpur University |
Koley K.,Jadavpur University |
Saha S.K.,Ultrasolar technology
IEEE Journal of the Electron Devices Society | Year: 2015
This paper presents the results of a systematic theoretical investigation on the impact of gate height on the analog and radio-frequency (RF) performances of underlap-FinFET devices. The conventional underlap-FinFETs offer lower on current (Ion) and higher distributed channel resistance (Rch). This paper shows that a higher gate height improves both Ion and Rch due to higher gate side-wall fringing fields. In this paper, the various figure of merits (FOMs) for analog applications of the underlap-FinFETs such as drain current (Ids) , transconductance (gm), transconductance generation factor (gm/Ids) , output resistance (Ro), and intrinsic gain (gmRo) are systematically analyzed for different values of gate height and reported. The RF FOMs studied include intrinsic capacitances (Cgs, Cgd) and resistances (Rgs, Rgd), transport delay (τm), cutoff frequency (fT), and the transit frequency of maximum available power gain (fMAX). This paper clearly demonstrates that the gate height is a critical technology parameter in improving the analog performance of underlap-FinFETs. © 2013 IEEE.
Vagues M.,Ultrasolar technology |
Kumar S.,Ultrasolar technology
2012 Proceedings of Portland International Center for Management of Engineering and Technology: Technology Management for Emerging Technologies, PICMET'12 | Year: 2012
This paper describes the transitioning of semiconductor foundries from "pure-play" manufacturing only to complete integrated circuit (IC) manufacturing turnkey solution provider. Today's model of semiconductor manufacturing is driven by design houses with dependency on packaging houses to define their package. Most of the packaging houses provide legacy packages to keep their operating cost low. So, value engineering for semiconductor manufacturing is slowly fading, giving rise to a gap that becomes mandatory for designers to think out of the box and provide higher density with multiple circuit functions, what is known today as the "System Design." Going beyond system design, we must be able to get closer to the end of the food chain and select providers who are creative from an end product design. In the microelectronics industry, a semiconductor foundry provides cost-effective IC manufacturing technology and wafer fabrication services to fabless IC design companies. However, besides contracting wafer fabrication, fabless companies, also require new product development (NPD) solutions including design collaboration, technology customization, device models, packaging solutions, and end product design. Therefore, the role of foundry has become extremely critical to drive NPD services and end-product solutions for customers. This paper describes the organization, functionality, and the role of foundries that must transition from pure-play wafer manufacturing to turnkey solution provider. Acquisition of these foundries and subcontractor manufacturers will be a huge part of the equation. © 2012 IEEE.
Ultrasolar technology | Date: 2014-07-31
A system can include at least one solar cell comprising a semiconductor material having p-n junctions formed therein; and a pulse generator electrically coupled to the solar cell and configured to apply electric pulses to dynamically alter a band gap of the semiconductor material as photons are received by the semiconductor material.
Ultrasolar technology | Date: 2014-10-20
At least one photovoltaic (PV) cell comprising a semiconductor material having p-n junctions formed therein, and configured to generate a PV output voltage in response to light; and a pulse generator coupled to receive a PV output voltage and generate electric output pulses therefrom, and apply such pulses to the PV cell.
Ultrasolar technology | Date: 2012-06-13
Ultrasolar technology | Date: 2011-06-15
A method to increase the efficiency of a solar cell comprises depositing a pyroelectric film on a surface of the solar cell and generating an electromotive force to bias the solar cell. The method also includes creation of an open circuit voltage. Further, the method includes increasing a short circuit current through the pyroelectric film and creating a sustained temperature variation in the solar cell. A constant temporal temperate gradient is created in the pyroelectric film to increase the short circuit current with a temperature. Further, a p-n junction is biased with the electromotive force produced from the pyroelectric film.
Ultrasolar technology | Date: 2011-12-07
A method, an apparatus and/or a system of non-decaying electric power generation from pyroelectric materials is disclosed. In one aspect, a method includes generating a substantially continuous electric energy from an at least one layer of pyroelectric material when the at least one layer of pyroelectric material is subjected to a temporal temperature gradient, a varying electric field and/or a mechanical oscillation. The method also includes creating the temporal temperature gradient, the varying electric field and/or the mechanical oscillation through coupling the at least one layer of pyroelectric material in between a first layer of a first material and a second layer of a second material that harnesses a heat energy and/or an electric field energy to produce the temporal temperature gradient and/or the mechanical oscillation to which the at least one layer of pyroelectric material is subjected
Ultrasolar technology | Date: 2012-06-13
apparatus for increasing output efficiency of solar modules for production of energy.