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Articles 1 - 30 of 60
Full-Text Articles in Electronic Devices and Semiconductor Manufacturing
A Semi-Empirical Model For Tilted-Gun Planar Magnetron Sputtering Accounting For Chimney Shadowing, Johnathan Bunn, C. Metting, Jason Hattrick-Simpers
A Semi-Empirical Model For Tilted-Gun Planar Magnetron Sputtering Accounting For Chimney Shadowing, Johnathan Bunn, C. Metting, Jason Hattrick-Simpers
Jason R. Hattrick-Simpers
No abstract provided.
Tunable Electromagnetic Bandgap Performance Of Coplanar Waveguides Periodically Loaded By Ferroelectric Varactors, D. Kuylenstierna, Guru Subramanyam, A. Vorobiev, S. Gevorgian
Tunable Electromagnetic Bandgap Performance Of Coplanar Waveguides Periodically Loaded By Ferroelectric Varactors, D. Kuylenstierna, Guru Subramanyam, A. Vorobiev, S. Gevorgian
Guru Subramanyam
To achieve tunable electromagnetic bandgap (EBG) performance, ferroelectric varactors are considered, in LC circuits, for periodically loading coplanar waveguides (CPWs). Asymmetric or symmetric tuning of the bandgap width may be achieved by changing the capacitance of the varactors in the LC circuits. To validate this concept, tunable EBG arrays based on silicon substrate CPWs, including thin film SrTiO3 (STO) varactors, are fabricated and tested experimentally. The EBGs are designed so that the first band gap starts between 20 and 30 GHz. Up to 10% tuning is achieved, under 20-V DC applied bias, in the EBG structures.
A New Method For Electrical Characterization Of Ferroelectric Thin Films At Microwave Frequencies, Guru Subramanyam
A New Method For Electrical Characterization Of Ferroelectric Thin Films At Microwave Frequencies, Guru Subramanyam
Guru Subramanyam
Read More: http://www.worldscientific.com/doi/abs/10.1142/S179329200900154X
Capacitance Of Thin-Film Ferroelectrics Under Different Drive Signals, Huadong Li, Guru Subramanyam
Capacitance Of Thin-Film Ferroelectrics Under Different Drive Signals, Huadong Li, Guru Subramanyam
Guru Subramanyam
Thin-film ferroelectric capacitance can be obtained by 2 different methods. Capacitance obtained using the derivative of its hysteresis loop is related to large applied signals and can be called the large-signal capacitance. Capacitance measured directly with a small, applied ac signal together with a slow changing dc bias is called the small-signal capacitance. This paper investigated the voltage dependence of the large- and small-signal capacitances. Measurements show that the large-signal C-V curve of thin-film ferroelectrics has much sharper peaks and higher peak values than the small-signal C-V curve. Analyses based on the Landau-Khalatnikov model shows that practical small-signal capacitance is …
Effect Of External Electrical Stimuli On Dna-Based Biopolymers, Guru Subramanyam, Carrie Bartsch, James Grote, Rajesh Naik, Lawrence Brott, Morley Stone, Angela Campbell
Effect Of External Electrical Stimuli On Dna-Based Biopolymers, Guru Subramanyam, Carrie Bartsch, James Grote, Rajesh Naik, Lawrence Brott, Morley Stone, Angela Campbell
Guru Subramanyam
Biopolymers, such as deoxyribonucleic acid-hexadecyltrimethyl ammonium chloride (DNA-CTMA) and bovine serum albumin-polyvinyl alcohol (BSA-PVA), were studied using a novel capacitive test structure. A variety of external electrical stimuli were applied, including a low frequency alternating current signal and a rf/microwave frequency signal combined with a DC bias. The dynamic responses of the DNA-based biopolymer to the external stimuli are presented in this paper. The electrical transport measurements support the space-charge-limited conduction and the low frequency capacitance–voltage (CV) measurements showed large depletion layer capacitance at the Au–biopolymer interface, at 20 Hz, and the capacitance approaching bulk values at 1 MHz. Electric …
Thermally Controlled Vanadium Dioxide Thin Film Microwave Devices, Guru Subramanyam, E. Shin, D. Brown, H. Yue
Thermally Controlled Vanadium Dioxide Thin Film Microwave Devices, Guru Subramanyam, E. Shin, D. Brown, H. Yue
Guru Subramanyam
No abstract provided.
Design Of A Si Mmic Compatible Ferroelectric Varactor Shunt Switch For Microwave Applications, Faruque Ahamed, Guru Subramanyam
Design Of A Si Mmic Compatible Ferroelectric Varactor Shunt Switch For Microwave Applications, Faruque Ahamed, Guru Subramanyam
Guru Subramanyam
This paper describes a capacitive shunt switch, based on ferroelectric varactors as a potential replacement for RF MEMS switches for microwave applications. Our implementation is based on a coplanar waveguide (CPW) transmission line shunted by a ferroelectric varactor. The novelty in the implementation comes from the elimination of any moving parts (as in MEMS switches) for switching. The concept of switching ON and OFF is based on the dielectric tunability of the ferroelectric material of barium strontium titanium oxide (BST) thin-films. From electromagnetic simulations performed, the isolation of the switch between 20 and 40 GHz (OFF state S21) is better …
Rf Performance Evaluation Of Ferroelectric Varactor Shunt Switches, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Robert Neidhard, Edward Nykiel, John Ebel, Richard Strawser, Keith Stamper, Mark Calcatera
Rf Performance Evaluation Of Ferroelectric Varactor Shunt Switches, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Robert Neidhard, Edward Nykiel, John Ebel, Richard Strawser, Keith Stamper, Mark Calcatera
Guru Subramanyam
No abstract provided.
Large Area Bst Thin Films For Microwave Applications Deposited By Pulsed Laser Ablation, C. Varanasi, K. Leedy, D. Tomich, Guru Subramanyam
Large Area Bst Thin Films For Microwave Applications Deposited By Pulsed Laser Ablation, C. Varanasi, K. Leedy, D. Tomich, Guru Subramanyam
Guru Subramanyam
Large area Ba1 − xSrxTiO3 (BST) thin films with x = 0.4 or x = 0.5 were deposited on 75 mm diameter Si wafers in a pulsed laser deposition (PLD) chamber enabling full-wafer device fabrication using standard lithography. The deposition conditions were re-optimized for large PLD chambers to obtain uniform film thickness, grain size, crystal structure, orientation, and dielectric properties of BST films. X-ray diffraction and microstructural analyses on the BST films grown on Pt/Au/Ti electrodes deposited on SiO2/Si wafers revealed films with (110) preferred orientation with a grain size < 100 nm. An area map of the thickness and crystal …
Highly Efficient Quantum-Dot Light Emitting Diodes With Dna-Ctma As Combined Hole Transporting And Electron-Blocking Layer, Q. Sun, Guru Subramanyam, Liming Dai, M. Check, A. Campbell, Rajesh Naik, James Grote, Yongqiang Wang
Highly Efficient Quantum-Dot Light Emitting Diodes With Dna-Ctma As Combined Hole Transporting And Electron-Blocking Layer, Q. Sun, Guru Subramanyam, Liming Dai, M. Check, A. Campbell, Rajesh Naik, James Grote, Yongqiang Wang
Guru Subramanyam
Owing to their narrow bright emission band, broad size-tunable emission wavelength, superior photostability, and excellent flexible-substrate compatibility, light-emitting diodes based on quantum dots (QD-LEDs) are currently under intensive research and development for multiple consumer applications including flat-panel displays and flat lighting. However, their commercialization is still precluded by the slow development to date of efficient QD-LEDs as even the highest reported efficiency of 2.0% cannot favorably compete with their organic counterparts. Here, we report QD-LEDs with a record high efficiency (∼4%), high brightness (∼6580 cd/m2), low turn-on voltage (∼2.6 V), and significantly improved color purity by simply using deoxyribonucleic acid …
Enhanced Dielectric Properties Of (Ba,Sr)Tio3//Ba(Zr,Ti)O-3 Heterostructures With Optimized Structure Design, Ming Liu, Jian Liu, Chunrui Ma, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Jie He, Jiechao Jiang, Efstathios Meletis, Amar Bhalla
Enhanced Dielectric Properties Of (Ba,Sr)Tio3//Ba(Zr,Ti)O-3 Heterostructures With Optimized Structure Design, Ming Liu, Jian Liu, Chunrui Ma, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Jie He, Jiechao Jiang, Efstathios Meletis, Amar Bhalla
Guru Subramanyam
Environment-friendly ferroelectric Mn:BST//Mn:BZT heterostructures were epitaxially deposited on (001) MgO substrates by pulsed laser deposition with different combination ratios of Mn:BST over Mn:BZT, 2.5:7.5; 1:1; and 7.5:2.5. The microstructural studies indicate that the in-plane interface relationships between the heterostructures and the substrate are determined to be (001)Mn:BST//(001)Mn:BZT//(001)MgO and [100]Mn:BST//[100]Mn:BZT//[100]MgO. The Ku band microwave (15.5–18 GHz) dielectric property characterizations show that the dielectric constant, dielectric loss, and tunabilities of the heterostructures are highly dependent upon the sequences of Mn:BST to Mn:BZT. The optimized dielectric tunability with a low loss tangent was found to be 58.1%–74.4% under the combination ratio of 1:1 …
A New Ferroelectric Varactor Shunt Switch For Microwave And Millimeterwave Reconfigurable Circuits, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Angela Campbell, Robert Neidhard, Edward Nykiel, Rebecca Cortez, Keith Stamper, Mark Calcatera
A New Ferroelectric Varactor Shunt Switch For Microwave And Millimeterwave Reconfigurable Circuits, Guru Subramanyam, Faruque Ahamed, Rand Biggers, Angela Campbell, Robert Neidhard, Edward Nykiel, Rebecca Cortez, Keith Stamper, Mark Calcatera
Guru Subramanyam
This paper presents a ferroelectric varactor shunt switch which can be useful for microwave/millimeterwave switching as well as for the design of reconfigurable circuits. The device operation is based on nonlinear dielectric tunability of a ferroelectric thin-film sandwiched between two metal layers in the parallel plate configuration. A CPW based design allows for MMIC compatible shunt switches with low insertion loss and high isolation. Experimental performance of the varactor shunt switch indicates good switching performance with ~24 dB isolation @41 GHz, and insertion loss below 7 dB up to 45 GHz.
Ferroelectric Thin-Film Based Two-Dimensional Electromagnetic Structures, U. Khan, Guru Subramanyam, S. Gevorgian, A. Vorobiev
Ferroelectric Thin-Film Based Two-Dimensional Electromagnetic Structures, U. Khan, Guru Subramanyam, S. Gevorgian, A. Vorobiev
Guru Subramanyam
A two-dimensional electromagnetic bandgap structure has been developed using ferroelectric thin-films. Using lumped inductors and parallel plate capacitors a planar structure is developed which creates a bandgap in the 20–40 GHz range, as demonstrated by experimental results. The ferroelectric material Ba0.6Sr0.4TiO3 (BST) is used in the form of a thin-film between patterned layers of gold to form capacitors on a 500 μm thick high-resistivity Si substrate. A meander line based design is used to form the two-dimensional surface which provides biasing pathways to the varactors. The concept is simulated and experimentally verified using a coplanar waveguide based device in which …
Performance Of Thin-Film Ferroelectric Capacitors For Emc Decoupling, Huadong Li, Guru Subramanyam
Performance Of Thin-Film Ferroelectric Capacitors For Emc Decoupling, Huadong Li, Guru Subramanyam
Guru Subramanyam
This paper studied the effects of thin-film ferroelectrics as decoupling capacitors for electromagnetic compatibility applications. The impedance and insertion loss of PZT capacitors were measured and compared with the results from commercial off-the-shelf capacitors. An equivalent circuit model was extracted from the experimental results, and a considerable series resistance was found to exist in ferroelectric capacitors. This resistance gives rise to the observed performance difference around series resonance between ferroelectric PZT capacitors and normal capacitors. Measurements on paraelectric (Ba,Sr)TiO3-based integrated varactors do not show this significant resistance. Some analyses were made to investigate the mechanisms, and it was …
A Memristor Device Model, Chris Yakopcic, Tarek Taha, Guru Subramanyam
A Memristor Device Model, Chris Yakopcic, Tarek Taha, Guru Subramanyam
Guru Subramanyam
This letter proposes a new mathematical model for memristor devices. It builds on existing models and is correlated against several published device characterizations. This letter identifies significant discrepancies between the existing models and published device characterization data. The proposed model addresses these discrepancies. In particular, it allows modeling of memristor-based neuromorphic systems.
Microwave Characterization Of Nanostructured Ferroelectric Ba0.6sr0.4tio3 Thin Films Fabricated By Pulsed Laser Deposition, Angela Campbell, Rand Biggers, Guru Subramanyam, Gregory Kozlowski, Richard Kleismit, Hollie Zate, Simon Hopkins, Bartek Glowacki, Bonnie Riehl, Timothy Peterson
Microwave Characterization Of Nanostructured Ferroelectric Ba0.6sr0.4tio3 Thin Films Fabricated By Pulsed Laser Deposition, Angela Campbell, Rand Biggers, Guru Subramanyam, Gregory Kozlowski, Richard Kleismit, Hollie Zate, Simon Hopkins, Bartek Glowacki, Bonnie Riehl, Timothy Peterson
Guru Subramanyam
A series of nanostructured ferroelectric thin films of barium strontium titanate were fabricated using a pulsed laser deposition system with real-time in situ process control. Pulsed laser deposition parameters were controlled during the growth of nanostructured thin films for use in the development of high frequency tunable microwave devices. The thin films were all grown at the same substrate temperature and laser beam energy density, but the chamber oxygen partial pressure (COPP) was varied systematically from 19 mTorr through 1000 Torr. Structural and electromagnetic characterization was performed using atomic force microscopy and evanescent microwave microscopy, respectively. Atomic force microscopy showed …
Microwave Dielectric Properties Of Dna Based Polymers Between 10 And 30 Ghz, Guru Subramanyam, E. Heckman, James Grote, K. Hopkins
Microwave Dielectric Properties Of Dna Based Polymers Between 10 And 30 Ghz, Guru Subramanyam, E. Heckman, James Grote, K. Hopkins
Guru Subramanyam
Deoxyribonucleic acid (DNA) based polymer thin-films were characterized at microwave frequencies for the first time. The dielectric properties of the film were extracted from comparison of the propagation constants of the co-planar waveguide (CPW) lines on bare MgO substrates and the DNA based films on MgO substrates. The insertion loss introduced by the DNA film is only 0.1 dB at 10 GHz and 0.5 dB at 30 GHz. The relative dielectric constant of the DNA based film averages to four at microwave frequencies, and the loss-tangent was below 0.1 up to 30 GHz.
Closed-Form Expression For The Net Ground Plane Inductance Of Coplanar Stripline Pcbs, Li Huadong, Guru Subramanyam
Closed-Form Expression For The Net Ground Plane Inductance Of Coplanar Stripline Pcbs, Li Huadong, Guru Subramanyam
Guru Subramanyam
The net ground plane inductance of printed circuit boards is the source of common-mode radiated emissions. Correct determination of the net ground plane inductance provides a quick estimation of the radiated emissions from printed circuit boards. Employing conformal mapping technique, this paper gives a closed-form expression for the per unit length net ground plane inductance of coplanar stripline printed circuit boards with finite ground plane width. Current density distribution on the ground plane is also obtained.
A Low Voltage Tunable Analog Phase Shifter Utilizing Ferroelectric Varactors, Guru Subramanyam, Kevin Leedy, Chakrapani Varanasi, Robert Neidhard, Keith Stamper, Mark Calcatera
A Low Voltage Tunable Analog Phase Shifter Utilizing Ferroelectric Varactors, Guru Subramanyam, Kevin Leedy, Chakrapani Varanasi, Robert Neidhard, Keith Stamper, Mark Calcatera
Guru Subramanyam
A distributed transmission line phase shifter was implemented by periodically loading a coplanar transmission line using ferroelectric varactors in a shunt configuration. A single dc bias applied to the phase shifter circuit provides a large relative phase shift. A relative phase shift of ∼ 305 degrees was obtained at 20 GHz for a dc bias of only 5 V.
Generalized Memristive Device Spice Model And Its Application In Circuit Design, Chris Yakopcic, Tarek Taha, Guru Subramanyam, R. Pino
Generalized Memristive Device Spice Model And Its Application In Circuit Design, Chris Yakopcic, Tarek Taha, Guru Subramanyam, R. Pino
Guru Subramanyam
This paper presents a SPICE model for memristive devices. It builds on existing models and is correlated against several published device characterization data with an average error of 6.04%. When compared to existing alternatives, the proposed model can more accurately simulate a wide range of published memristors. The model is also tested in large circuits with up to 256 memristors, and was less likely to cause convergence errors when compared to other models. We show that the model can be used to study the impact of memristive device variation within a circuit. We examine the impact of nonuniformity in device …
Microwave Dielectric Properties Of Epitaxial Mn-Doped Ba(Zr,Ti)O-3 Thin Films On Laalo3 Substrates, Ming Liu, Chunrui Ma, Jian Liu, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Chao Dai, Yuan Lin, Amar Bhalla
Microwave Dielectric Properties Of Epitaxial Mn-Doped Ba(Zr,Ti)O-3 Thin Films On Laalo3 Substrates, Ming Liu, Chunrui Ma, Jian Liu, Gregory Collins, Chonglin Chen, Andy Alemayehu, Guru Subramanyam, Chao Dai, Yuan Lin, Amar Bhalla
Guru Subramanyam
Environmental friendly ferroelectric relaxor Ba(Zr0.2Ti0.8)O3 thin films with an additional 2% Mn dopant were epitaxially fabricated on the (001) LaAlO3 single crystal substrates by pulsed laser deposition. Microstructure characterizations from x-ray diffraction suggest that the films are c-axis oriented with the interface relationship of [101]Mn:BZT//[100]LAO and (001)Mn:BZT //(001)LAO. The microwave dielectric property measurements (13–17.5 GHz) reveal that the films have excellent dielectric properties with large tunability, high dielectric constant, and low dielectric loss, which the average value is 25.9%, 169 and 0.054, respectively. It is indicated that the additional 2% Mn doped Ba(Zr0.2Ti0.8)O3 thin films can be used for the …
Influence Of Space-Charge On Hysteresis Loop Characteristics Of Ferroelectric Thin Films, Huadong Li, Guru Subramanyam, S. Dey
Influence Of Space-Charge On Hysteresis Loop Characteristics Of Ferroelectric Thin Films, Huadong Li, Guru Subramanyam, S. Dey
Guru Subramanyam
Hysteresis loops of Pb(Zr, Ti)O3 (PZT) thin films obtained by using a Sawyer-Tower (ST) circuit are affected by many factors. This paper investigated the influence of space charge on the hysteresis loop of thin-film ferroelectrics, based on the model that polarization consists of two parts: linear and switching polarization. It is found that the space charge affects both the shape and offset of the ideal hysteresis loop. Further investigation shows that the practical hysteresis loop has a close relationship with the equivalent ST circuit parameters: the leakage resistance of the FE film, the equivalent input impedance of the measurement equipment, …
Novel Multi-Capacitor Architecture For Bst Thin Film Varactors, Guru Subramanyam, M. Patterson, K. Leedy, R. Neidhard, C. Varanasi, G. Steinhauer
Novel Multi-Capacitor Architecture For Bst Thin Film Varactors, Guru Subramanyam, M. Patterson, K. Leedy, R. Neidhard, C. Varanasi, G. Steinhauer
Guru Subramanyam
Novel Barium Strontium Titanate (BST) thin film varactors with parallel capacitor architecture were designed fabricated and tested. Varactors with 2–6 parallel capacitors were experimentally verified using large area processed bst thin films. The multicapacitor varactor shunt switches provided improved isolation at the expense of higher insertion loss. The multicapacitor varactors yielded reduced overall parasitic series inductance and resistances, resulting in higher quality factor Q. This is the first time such a device is reported.
Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, Huadong Li, Guru Subramanyam, Jiadong Wang
Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, Huadong Li, Guru Subramanyam, Jiadong Wang
Guru Subramanyam
This paper studied the effect of dopant-ion charges on the performance of thin film ferroelectrics. Field distributions and capacitance of ferroelectric thin films with different dopant-ion charge densities are analyzed. The non-linearity of the electric field inside the thin film increases with the dopant-ion charge density and decreases with the linear permittivity of the ferroelectric thin film. Once the applied voltage is strong enough, the field distribution will become linear. The FE thin film peak capacitance reduces with the dopant-ion charge density and the total area under the C-V curve between two large voltages with opposite signs is fixed.
Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, S. Dey, C. Wang, W. Cao, S. Bhaskar, J. Li, Guru Subramanyam
Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, S. Dey, C. Wang, W. Cao, S. Bhaskar, J. Li, Guru Subramanyam
Guru Subramanyam
Frequency and phase agile microwave components such as tunable filters and phase shifters will require ferroelectric thin films that exhibit a nonlinear dependence of dielectric permittivity (ɛ r ) with dc electric bias, as well as a high material (Δɛ r /tan δ) and device (or K-factor in phase shift/dB) figure of merits (FOM). Therefore, voltage tunable (Pb0.3Sr0.7)TiO3 (PST) thin films (90–150 nm) on (0001) sapphire were deposited by metal-organic chemical vapor deposition at rates of 10–15 nm/min. The as-deposited epitaxial PST films were characterized by Rutherford backscattering spectroscopy, X-ray methods, field …
Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi
Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi
Tianxiang Nan
This paper reports on the first demonstration of an ultra-miniaturized, high frequency (215 MHz) and high sensitivity MEMS resonant magnetic field sensor based on an AlN/FeGaB bilayer nano-plate resonator capable of detecting magnetic field at nano-Tesla level. Despite of the reduced volume and the high operating frequency of the sensor, high electromechanical performances were achieved (quality factor Q ≈ 511 and electromechanical coupling coefficient kt² ≈ 1.63%). This first prototype was characterized for different magnetic field levels from 0 to 152 Oe showing a frequency sensitivity of ~ 1 Hz/nT and a limit of detection of ~ 10 nT.
A Shade Tolerant Panel Design For Thin Film Photovoltaics, Sourabh Dongaonkar, Muhammad Alam
A Shade Tolerant Panel Design For Thin Film Photovoltaics, Sourabh Dongaonkar, Muhammad Alam
Sourabh Dongaonkar
We analyze the problem of partial shading of thin film photovoltaic (TFPV) panels, using full two dimensional circuit simulations. By accounting for the panel structure and typical array configurations, we can accurately account for the effect of various shading configurations at the cell and panel level. We demonstrate the limitation of external bypass diodes in protecting shaded cells from reverse breakdown, and explore the whole range of shading scenarios and their impact on reverse stress experienced by shaded cells. Based on the analysis, we identify the key aspects of shading problem, and formulate design rules for shadow aware geometrical design …
End-To-End Modeling For Variability And Reliability Analysis Of Thin Film Pv, Sourabh Dongaonkar, Muhammad Alam
End-To-End Modeling For Variability And Reliability Analysis Of Thin Film Pv, Sourabh Dongaonkar, Muhammad Alam
Sourabh Dongaonkar
We present an end-to-end modeling framework, spanning the device, module and also system levels, for analyzing thin film photovoltaics (PV). This approach is based on embedding a detailed, statistically relevant, physics based equivalent circuit into module and array level simulations. This approach enables us to analyze key variability and reliability issues in thin film PV, and allows us to interpret their effect on process yield and intrinsic module lifetimes. Our results suggest that the time-zero gap between cell and module efficiencies, a key variability concern for thin-film PV, can be attributed to processrelated shunts with log-normal PDF distributed randomly across …
Reverse Stress Metastability Of Shunt Current In Cigs Solar Cells, Sourabh Dongaonkar, Erik Sheets, Rakesh Agrawal, Muhammad Alam
Reverse Stress Metastability Of Shunt Current In Cigs Solar Cells, Sourabh Dongaonkar, Erik Sheets, Rakesh Agrawal, Muhammad Alam
Sourabh Dongaonkar
Partial shading in thin film solar panels can result in reverse bias stress across shaded cells. Therefore, it is important to understand the effect of such reverse stress in commercially competitive PV technologies such as CIGS. In this paper, we systematically investigate the effect of moderate reverse bias on solution-processed CIGS solar cells. We subject the solar cells to varying degrees of reverse biases and continuously monitor the impact of the stress on dark current. We also explore the relaxation behavior of dark current following passive storage and the long term effect of the shadow stress on power output of …
A Physical Model For Non-Ohmic Shunt Conduction And Metastability In Amorphous Silicon P-I-N Solar Cells, Sourabh Dongaonkar, Karthik Y, Souvik Mahapatra, Muhammad Alam
A Physical Model For Non-Ohmic Shunt Conduction And Metastability In Amorphous Silicon P-I-N Solar Cells, Sourabh Dongaonkar, Karthik Y, Souvik Mahapatra, Muhammad Alam
Sourabh Dongaonkar
We present a physical model of non-ohmic shunt current in a-Si:H p-i-n solar cells, and validate it with detailed measurements. This model is based on space-charge-limited (SCL) transport through localized p-i-p shunt paths, which can arise from contact metal incorporation in a-Si:H layer. This model explains both the electrical characteristics and the metastable switching behavior of the shunts within an integrated framework. We first verify the SCL model using simulations and statistically robust measurements, and then use this picture to analyze our systematic observations of non-volatile switching in these shunts. Our work not only resolves broad experimental observations on shunt …