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Articles 1 - 27 of 27
Full-Text Articles in Engineering
Runtime Performance Of Gamess Quantum Chemistry Application Offloaded To Gpus, Masha Sosonkina, Gabriel Mateescu, Peng Xu, Tosaporn Sattasathuchana, Buu Pham, Mark S. Gordon, Sarom S. Leang
Runtime Performance Of Gamess Quantum Chemistry Application Offloaded To Gpus, Masha Sosonkina, Gabriel Mateescu, Peng Xu, Tosaporn Sattasathuchana, Buu Pham, Mark S. Gordon, Sarom S. Leang
Electrical & Computer Engineering Faculty Publications
Computational chemistry is at the forefront of solving urgent societal problems, such as polymer upcycling and carbon capture. The complexity of modeling these processes at appropriate length and time scales is mainly manifested in the number and types of chemical species involved in the reactions and may require models of several thousand atoms and large basis sets to accurately capture the chemical complexity and heterogeneity in the physical and chemical processes. The quantum chemistry package General Atomic and Molecular Electronic Structure System (GAMESS) has a wide array of methods that can efficiently and accurately treat complex chemical systems. In this …
Continuity Of Formal Power Series Products In Nonlinear Control Theory, W. Steven Gray, Mathias Palmstrøm, Alexander Schmeding
Continuity Of Formal Power Series Products In Nonlinear Control Theory, W. Steven Gray, Mathias Palmstrøm, Alexander Schmeding
Electrical & Computer Engineering Faculty Publications
Formal power series products appear in nonlinear control theory when systems modeled by Chen–Fliess series are interconnected to form new systems. In fields like adaptive control and learning systems, the coefficients of these formal power series are estimated sequentially with real-time data. The main goal is to prove the continuity and analyticity of such products with respect to several natural (locally convex) topologies on spaces of locally convergent formal power series in order to establish foundational properties behind these technologies. In addition, it is shown that a transformation group central to describing the output feedback connection is in fact an …
8-Plate Multi-Resonant Coupling Using A Class-E2 Power Converter For Misalignments In Capacitive Wireless Power Transfer, Yashwanth Bezawada, Shirshak K. Dhali
8-Plate Multi-Resonant Coupling Using A Class-E2 Power Converter For Misalignments In Capacitive Wireless Power Transfer, Yashwanth Bezawada, Shirshak K. Dhali
Electrical & Computer Engineering Faculty Publications
Misalignment is a common issue in wireless power transfer systems. It shifts the resonant frequency away from the operating frequency that affects the power flow and efficiency from the charging station to the load. This work proposes a novel capacitive wireless power transfer (CPT) using an 8-plate multi-resonant capacitive coupling to minimize the effect of misalignments. A single-active switch class-E2 power converter is utilized to achieve multi-resonance through the selection of different resonant inductors. Simulations show a widening of the resonant frequency band which offers better performance than a regular 4-plate capacitive coupling for misalignments. The hardware results of …
Spectrum Sensing With Energy Detection In Multiple Alternating Time Slots, Călin Vlădeanu, Alexandru Marţian, Dimitrie C. Popescu
Spectrum Sensing With Energy Detection In Multiple Alternating Time Slots, Călin Vlădeanu, Alexandru Marţian, Dimitrie C. Popescu
Electrical & Computer Engineering Faculty Publications
Energy detection (ED) represents a low complexity approach used by secondary users (SU) to sense spectrum occupancy by primary users (PU) in cognitive radio (CR) systems. In this paper, we present a new algorithm that senses the spectrum occupancy by performing ED in K consecutive sensing time slots starting from the current slot and continuing by alternating before and after the current slot. We consider a PU traffic model specified in terms of an average duty cycle value, and derive analytical expressions for the false alarm probability (FAP) and correct detection probability (CDP) for any value of K . Our …
Runtime Power Allocation Based On Multi-Gpu Utilization In Gamess, Masha Sosonkina, Vaibhav Sundriyal, Jorge Luis Galvez Vallejo
Runtime Power Allocation Based On Multi-Gpu Utilization In Gamess, Masha Sosonkina, Vaibhav Sundriyal, Jorge Luis Galvez Vallejo
Electrical & Computer Engineering Faculty Publications
To improve the power consumption of parallel applications at the runtime, modern processors provide frequency scaling and power limiting capabilities. In this work, a runtime strategy is proposed to maximize performance under a given power budget by distributing the available power according to the relative GPU utilization. Time series forecasting methods were used to develop workload prediction models that provide accurate prediction of GPU utilization during application execution. Experiments were performed on a multi-GPU computing platform DGX-1 equipped with eight NVIDIA V100 GPUs used for quantum chemistry calculations in the GAMESS package. For a limited power budget, the proposed strategy …
Grand Challenges In Low Temperature Plasmas, Xinpei Lu, Peter J. Bruggeman, Stephan Reuter, George Naidis, Annemie Bogaerts, Mounir Laroussi, Michael Keidar, Eric Robert, Jean-Michel Pouvesle, Dawei Liu, Kostya (Ken) Ostrikov
Grand Challenges In Low Temperature Plasmas, Xinpei Lu, Peter J. Bruggeman, Stephan Reuter, George Naidis, Annemie Bogaerts, Mounir Laroussi, Michael Keidar, Eric Robert, Jean-Michel Pouvesle, Dawei Liu, Kostya (Ken) Ostrikov
Electrical & Computer Engineering Faculty Publications
Low temperature plasmas (LTPs) enable to create a highly reactive environment at near ambient temperatures due to the energetic electrons with typical kinetic energies in the range of 1 to 10 eV (1 eV = 11600K), which are being used in applications ranging from plasma etching of electronic chips and additive manufacturing to plasma-assisted combustion. LTPs are at the core of many advanced technologies. Without LTPs, many of the conveniences of modern society would simply not exist. New applications of LTPs are continuously being proposed. Researchers are facing many grand challenges before these new applications can be translated to practice. …
Entropy Of Generating Series For Nonlinear Input-Output Systems And Their Interconnections, W. Steven Gray
Entropy Of Generating Series For Nonlinear Input-Output Systems And Their Interconnections, W. Steven Gray
Electrical & Computer Engineering Faculty Publications
This paper has two main objectives. The first is to introduce a notion of entropy that is well suited for the analysis of nonlinear input-output systems that have a Chen-Fliess series representation. The latter is defined in terms of its generating series over a noncommutative alphabet. The idea is to assign an entropy to a generating series as an element of a graded vector space. The second objective is to describe the entropy of generating series originating from interconnected systems of Chen-Fliess series that arise in the context of control theory. It is shown that one set of interconnections can …
A Case Study: Influence Of Circuit Impedance On The Performance Of Class-E² Resonant Power Converter For Capacitive Wireless Power Transfer, Yashwanth Bezawada, Yucheng Zhang
A Case Study: Influence Of Circuit Impedance On The Performance Of Class-E² Resonant Power Converter For Capacitive Wireless Power Transfer, Yashwanth Bezawada, Yucheng Zhang
Electrical & Computer Engineering Faculty Publications
The evolution of power electronics led to rapid development in wireless charging technology; as a result, a single active switch topology was introduced. The present market utilizes inductive wireless power transfer (IPT); because of the disadvantages of cost, size, and safety concerns, research on wireless power transfer was diverted towards capacitive wireless power transfer (CPT). This paper studies the optimal impedance tracking of the capacitive wireless power transfer system for maximum power transfer. Compared to prior methods developed for maximum power point tracking in power control, this paper proposes a new approach by means of finding impedance characteristics of the …
Transient Behavior Of Drift And Ionization In Atmospheric Pressure Nitrogen Discharge, S. K. Dhali
Transient Behavior Of Drift And Ionization In Atmospheric Pressure Nitrogen Discharge, S. K. Dhali
Electrical & Computer Engineering Faculty Publications
The fluid models are frequently used to describe a non-thermal plasma such as a streamer discharge. The required electron transport data and rate coefficients for the fluid model are parametrized using the local field approximation (LFA) in first order models and the local-mean-energy approximation (LMEA) in second order models. We performed Monte Carlo simulations in Nitrogen gas with step changes in the E/N (reduced electric field) to study the behavior of the transport properties in the transient phase. During the transient phase of the simulation, we extract the instantaneous electron mean energy, which is different from the steady state mean …
Assessment Of Cu(In, Ga)Se₂ Solar Cells Degradation Due To Water Ingress Effect On The Cds Buffer Layer, Deewakar Poudel, Benjamin Belfore, Shankar Karki, Grace Rajan, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac
Assessment Of Cu(In, Ga)Se₂ Solar Cells Degradation Due To Water Ingress Effect On The Cds Buffer Layer, Deewakar Poudel, Benjamin Belfore, Shankar Karki, Grace Rajan, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac
Electrical & Computer Engineering Faculty Publications
The effect of water ingress on the surface of the buffer layer of a Cu(In, Ga)Se2 (CIGS) solar cell was studied. Such degradation can occur either during the fabrication process, if it involves a chemical bath as is often the case for CdS, or while the modules are in the field and encapsulants degrade. To simulate the impact of this moisture ingress, devices with a structure sodalime glass/Mo/CIGS/CdS were immersed in deionized water. The thin films were then analyzed both pre and post water soaking. Dynamic secondary ion mass spectroscopy (SIMS) was performed on completed devices to analyze impurity diffusion …
High Voltage Design And Evaluation Of Wien Filters For The Cebaf 200 Kev Injector Upgrade, Gabriel Palacios-Serrano, Helmut Baumgart, C. Hernández-García, P. Adderley, J. Benesch, D. Bullard, J. Grames, A. Hofler, D. Machie, M. Poelker, M. Stutzman, R. Suleiman
High Voltage Design And Evaluation Of Wien Filters For The Cebaf 200 Kev Injector Upgrade, Gabriel Palacios-Serrano, Helmut Baumgart, C. Hernández-García, P. Adderley, J. Benesch, D. Bullard, J. Grames, A. Hofler, D. Machie, M. Poelker, M. Stutzman, R. Suleiman
Electrical & Computer Engineering Faculty Publications
High-energy nuclear physics experiments at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF) require highly spin-polarization electron beams, produced from strained super-lattice GaAs photocathodes, activated to negative electron affinity in a photogun operating at 130 kV dc. A pair of Wien filter spin rotators in the injector defines the orientation of the electron beam polarization at the end station target. An upgrade of the CEBAF injector to better support the upcoming MOLLER experiment requires increasing the electron beam energy to 200 keV, to reduce unwanted helicity correlated intensity and position systematics and provide precise control of the polarization orientation. …
Logical Modeling Of Adiabatic Logic Circuits Using Vhdl, Lee Belfore
Logical Modeling Of Adiabatic Logic Circuits Using Vhdl, Lee Belfore
Electrical & Computer Engineering Faculty Publications
The underlying nature of adiabatic circuits is most accurately characterized at the circuit level as it is for traditional technologies. In order to scale system designs for adiabatic logic technologies, modeling of adiabatic circuits at the logic level is necessary. Logic level models of adiabatic logic circuits can facilitate the design, development, and verification of large scale digital systems that may be infeasible using circuit simulators. Adiabatic logic circuits can be powered with a four stage power clock consisting of idle, charge, hold, and recover stages that provides for adiabatic charging and charge recovery to give adiabatic circuits their low …
Fault Protection Considerations For Mvdc Shipboard Power Systems Operating With Pulsed-Power Loads, Marounfa Djibo, Paul Moses, Ike Flory
Fault Protection Considerations For Mvdc Shipboard Power Systems Operating With Pulsed-Power Loads, Marounfa Djibo, Paul Moses, Ike Flory
Electrical & Computer Engineering Faculty Publications
Medium Voltage Direct Current (MVDC) power distribution architectures are of immense interest for various shipboard power applications due to their advantages over classical MVAC distribution systems with respect to power quality, power density, and efficiency. However, MVDC are far away from maturity when compared to MVAC with respect to fault detection and isolation. Currently, there are no standards available for applying MVDC protection systems in shipboard applications. Furthermore, due to the absence of zero crossings in DC waveforms and unique transient fault signatures, it is challenging to design effective protection system schemes to isolate faults via conventional protection systems. This …
Assessment Of Cable Length Limit For Effective Protection By Z-Source Circuit Breakers In Dc Power Networks, Ruiyun Fu, Sagar Bhatta, Joseph M. Keller, Yucheng Zhang
Assessment Of Cable Length Limit For Effective Protection By Z-Source Circuit Breakers In Dc Power Networks, Ruiyun Fu, Sagar Bhatta, Joseph M. Keller, Yucheng Zhang
Electrical & Computer Engineering Faculty Publications
This paper introduces groundbreaking research on how to assess the Cable Length Limit (CLL) to ensure effective protection by Z-source Circuit Breakers (ZCBs) in DC power networks. It has been revealed that the line parameters of power cables have a significant impact on the cutoff performance of ZCBs. The question of assessing the CLL has been raised as an unsolved problem. In this paper, a method of CLL assessment is proposed based on physical models and simulation tests. To verify the proposed method, two studies were performed to assess the Cable Length Limits depending on fault levels and power delivery …
Distributed Strategy For Power Re-Allocation In High Performance Applications, Vaibhav Sundriyal, Masha Sosonkina
Distributed Strategy For Power Re-Allocation In High Performance Applications, Vaibhav Sundriyal, Masha Sosonkina
Electrical & Computer Engineering Faculty Publications
To improve the power consumption of parallel applications at the runtime, modern processors provide frequency scaling and power limiting capabilities. In this work, a runtime strategy is proposed to distribute a given power allocation among the cluster nodes assigned to the application while balancing their performance change. The strategy operates in a timeslice-based manner to estimate the current application performance and power usage per node followed by power redistribution across the nodes. Experiments, performed on four nodes (112 cores) of a modern computing platform interconnected with Infiniband showed that even a significant power budget reduction of 20% may result in …
Real-Time Optimization Of Anti-Reflective Coatings For Cigs Solar Cells, Grace Rajan, Shankar Karki, Robert W. Collins, Nikolas J. Podraza, Sylvain Marsillac
Real-Time Optimization Of Anti-Reflective Coatings For Cigs Solar Cells, Grace Rajan, Shankar Karki, Robert W. Collins, Nikolas J. Podraza, Sylvain Marsillac
Electrical & Computer Engineering Faculty Publications
A new method combining in-situ real-time spectroscopic ellipsometry and optical modeling to optimize the thickness of an anti-reflective (AR) coating for Cu(In,Ga)Se2 (CIGS) solar cells is described and applied directly to fabricate devices. The model is based on transfer matrix theory with input from the accurate measurement of complex dielectric function spectra and thickness of each layer in the solar cell by spectroscopic ellipsometry. The AR coating thickness is optimized in real time to optically enhance device performance with varying thickness and properties of the constituent layers. Among the parameters studied, we notably demonstrate how changes in thickness of …
Advances In Atomic Layer Deposition (Ald) Nanolaminate Synthesis Of Thermoelectric Films In Porous Templates For Improved Seebeck Coefficient, Xin Chen, Helmut Baumgart
Advances In Atomic Layer Deposition (Ald) Nanolaminate Synthesis Of Thermoelectric Films In Porous Templates For Improved Seebeck Coefficient, Xin Chen, Helmut Baumgart
Electrical & Computer Engineering Faculty Publications
Thermoelectrics is a green renewable energy technology which can significantly contribute to power generation due to its potential in generating electricity out of waste heat. The main challenge for the development of thermoelectrics is its low conversion efficiency. One key strategy to improve conversion efficiency is reducing the thermal conductivity of thermoelectric materials. In this paper, the state-of-the-art progresses made in improving thermoelectric materials are reviewed and discussed, focusing on phononic engineering via applying porous templates and ALD deposited nanolaminates structure. The effect of nanolaminates structure and porous templates on Seebeck coefficient, electrical conductivity and thermal conductivity, and hence in …
Maximizing Performance Under A Power Constraint On Modern Multicore Systems, Vaibhav Sundriyal, Masha Sosonkina, Bryce Westheimer, Mark S. Gordon
Maximizing Performance Under A Power Constraint On Modern Multicore Systems, Vaibhav Sundriyal, Masha Sosonkina, Bryce Westheimer, Mark S. Gordon
Electrical & Computer Engineering Faculty Publications
Energy efficiency and energy-proportional computing have become a central focus in modern supercomputers. These supercomputers should provide high throughput per unit of power to be sustainable in terms of operating cost and failure rates. In this paper, a power-bounded strategy is proposed that maximizes parallel application performance under a given power constraint. The strategy dynamically allocates power to core, uncore, and memory power domains within a node to maximize performance under a given power budget. Experiments on a 20-core Haswell-EP platform for a real-world parallel application GAMESS demonstrate that the proposed strategy delivers performance within 4% of the best possible …
Core And Uncore Joint Frequency Scaling Strategy, Vaibhav Sundriyal, Masha Sosonkina, Bryce Westheimer, Mark Gordon
Core And Uncore Joint Frequency Scaling Strategy, Vaibhav Sundriyal, Masha Sosonkina, Bryce Westheimer, Mark Gordon
Electrical & Computer Engineering Faculty Publications
Energy-proportional computing is one of the foremost constraints in the design of next generation exascale systems. These systems must have a very high FLOP-per-watt ratio to be sustainable, which requires tremendous improvements in power efficiency for modern computing systems. This paper focuses on the processor—as still the biggest contributor to the power usage—by considering both its core and uncore power subsystems. The uncore describes those processor functions that are not handled by the core, such as L3 cache and on-chip interconnect, and contributes significantly to the total system power. The uncore frequency scaling (UFS) capability has been available to the …
Novel Contact Materials For Improved Performance Cdte Solar Cells, Angus Rocket, Robert Collins, Sylvain Marsillac
Novel Contact Materials For Improved Performance Cdte Solar Cells, Angus Rocket, Robert Collins, Sylvain Marsillac
Electrical & Computer Engineering Faculty Publications
This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe2:N, a-Si:H and alloys with C, and FeS2. Improved contacts were achieved with FeS2. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research …
Temporary Bonding With Polydimethylglutarimide Based Lift Off Resist As A Layer Transfer Platform, T. Matsumae, A. D. Koehler, J. D. Greenlee, T. J. Anderson, H. Baumgart, G. G. Jernigan, K. D. Hobart, F. J. Kub
Temporary Bonding With Polydimethylglutarimide Based Lift Off Resist As A Layer Transfer Platform, T. Matsumae, A. D. Koehler, J. D. Greenlee, T. J. Anderson, H. Baumgart, G. G. Jernigan, K. D. Hobart, F. J. Kub
Electrical & Computer Engineering Faculty Publications
Bonding of lift off resist (LOR) was performed to realize temporary wafer bonding without residue. Bonding process conditions such as spin speed, pre-bake temperature, and bonding temperature were optimized to obtain a large bonded area with high bond strength. Under optimized process conditions, a bonded area covering over 98% of the wafer surface, with a room temperature bond strength of nearly 5 J/m2 is achieved. During razor blade testing, fracture often occurs at the Si wafer. Moreover, debonding using an N-Methyl-2-pyrrolidone (NMP)-based solvent left the wafer surface extremely small amount of residue. Thus, the optimized bonding processed developed in …
On The Radius Of Convergence Of Interconnected Analytic Nonlinear Input-Output Systems, Makhin Thitsa, W. Steven Gray
On The Radius Of Convergence Of Interconnected Analytic Nonlinear Input-Output Systems, Makhin Thitsa, W. Steven Gray
Electrical & Computer Engineering Faculty Publications
A complete analysis is presented of the radii of convergence of the parallel, product, cascade and feedback interconnections of analytic nonlinear input-output systems represented as Fliess operators. Such operators are described by convergent functional series, which are indexed by words over a noncommutative alphabet. Their generating series are therefore specified in terms of noncommutative formal power series. Given growth conditions for the coefficients of the generating series for the subsystems, the radius of convergence of each interconnected system is computed assuming the subsystems are either all locally convergent or all globally convergent. In the process of deriving the radius of …
In Situ And Ex Situ Studies Of Molybdenum Thin Films Deposited By Rf And Dc Magnetron Sputtering As A Back Contact For Cigs Solar Cells, K. P. Aryal, H. Khatri, R. W. Collins, S. Marsillac
In Situ And Ex Situ Studies Of Molybdenum Thin Films Deposited By Rf And Dc Magnetron Sputtering As A Back Contact For Cigs Solar Cells, K. P. Aryal, H. Khatri, R. W. Collins, S. Marsillac
Electrical & Computer Engineering Faculty Publications
Molybdenum thin films were deposited by rf and dc magnetron sputtering and their properties analyzed with regards to their potential application as a back contact for CIGS solar cells. It is shown that both types of films tend to transition from tensile to compressive strain when the deposition pressure increases, while the conductivity and the grain size decreas. The nucleation of the films characterized by in situ and real time spectroscopic ellipsometry shows that both films follow a Volmer-Weber growth, with a higher surface roughness and lower deposition rate for the rf deposited films. The electronic relaxation time was then …
Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin
Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin
Electrical & Computer Engineering Faculty Publications
We propose coupled cavities to realize a strong enhancement of the Raman scattering. Five sub cavities are embedded in the photonic crystals. Simulations through finite-difference time-domain (FDTD) method demonstrate that one cavity, which is used to propagate the pump beam at the optical-communication wavelength, has a Q factor as high as 1.254 × 108 and modal volume as small as 0.03μm3 (0.3192(λ/n)3). These parameters result in ultra-small threshold lasing power ~17.7nW and 2.58nW for Stokes and anti-Stokes respectively. The cavities are designed to support the required Stokes and anti-Stokes modal spacing in silicon. The proposed structure …
Microbubble-Based Model Analysis Of Liquid Breakdown Initiation By A Submicrosecond Pulse, J. Qian, R. P. Joshi, K. H. Schoenbach, J. Dickens, A. Neuber, M. Butcher, M. Cevallos, H. Krompholz, E. Schamiloglu, J. Gaudet
Microbubble-Based Model Analysis Of Liquid Breakdown Initiation By A Submicrosecond Pulse, J. Qian, R. P. Joshi, K. H. Schoenbach, J. Dickens, A. Neuber, M. Butcher, M. Cevallos, H. Krompholz, E. Schamiloglu, J. Gaudet
Electrical & Computer Engineering Faculty Publications
An electrical breakdown model for liquids in response to a submicrosecond(∼100ns) voltage pulse is presented, and quantitative evaluations carried out. It is proposed that breakdown is initiated by field emission at the interface of pre-existing microbubbles. Impact ionization within the microbubble gas then contributes to plasma development, with cathode injection having a delayed and secondary role. Continuous field emission at the streamer tip contributes to filament growth and propagation. This model can adequately explain almost all of the experimentally observed features, including dendritic structures and fluctuations in the prebreakdown current. Two-dimensional, time-dependent simulations have been carried out based on a …
Cuin1-Xalxse2 Thin Films And Solar Cells, P. D. Paulson, M. W. Haimbodi, S. Marsillac, R. W. Birkmire, W. N. Shafarman
Cuin1-Xalxse2 Thin Films And Solar Cells, P. D. Paulson, M. W. Haimbodi, S. Marsillac, R. W. Birkmire, W. N. Shafarman
Electrical & Computer Engineering Faculty Publications
CuIn[sub 1-x]Al[sub x]Se[sub 2] thin films are investigated for their application as the absorber layer material for high efficiency solar cells. Single-phase CuIn[sub 1-x]Al[sub x]Se[sub 2] films were deposited by four source elemental evaporation with a composition range of 0≤x≤0.6. All these films demonstrate a normalized subband gap transmission >85% with 2 µm film thickness. Band gaps obtained from spectroscopic ellipsometry show an increase with the Al content in the CuIn[sub 1-x]Al[sub x]Se[sub 2] film with a bowing parameter of 0.62. The structural properties investigated using x-ray diffraction measurements show a decrease in lattice spacing as the Al content increases. …
High-Efficiency Solar Cells Based On Cu(Inal)Se[Sub 2] Thin Films, S. Marsillac, P. D. Paulson, M. W. Haimbodi, R. W. Birkmire, W. N. Shafarman
High-Efficiency Solar Cells Based On Cu(Inal)Se[Sub 2] Thin Films, S. Marsillac, P. D. Paulson, M. W. Haimbodi, R. W. Birkmire, W. N. Shafarman
Electrical & Computer Engineering Faculty Publications
A Cu(InAl)Se2solar cell with 16.9% efficiency is demonstrated using a Cu(InAl)Se2thin film deposited by four-source elemental evaporation and a device structure of glass/Mo/Cu(InAl)Se2/CdS/ZnO/indium tin oxide/(Ni/Algrid)/MgF2. A key to high efficiency is improved adhesion between the Cu(InAl)Se2 and the Mo back contact layer, provided by a 5-nm-thick Ga interlayer, which enabled the Cu(InAl)Se2 to be deposited at a 530 °C substrate temperature. Film and device properties are compared to Cu(InGa)Se2 with the same band gap of 1.16 eV. The solar cells have similar behavior, with performance limited by recombination through …