Dan Hampton and Tim Gfroerer , Davidson College, Davidson, NC

Slides:

Advertisements

Similar presentations

Study of Radiative and Heat-Generating Recombination in GaAs Ryan Crum and Tim Gfroerer, Davidson College, Davidson, NC Mark Wanlass, National Renewable.

Advertisements

E bb **. E Looking only at this region in the Rectangle:

Defects in solar cell materials: the good, the bad, and the ugly Tim Gfroerer Davidson College, Davidson, NC with Yong Zhang University of Charlotte.

Charge carriers must move to accommodate the bias-dependent depletion layer edge in a diode. Meanwhile, the capacitance depends on the position of the.

Conclusions and Acknowledgements Theoretical Fits Novel Materials for Heat-Based Solar Cells We are studying a set of materials that may be useful for.

Radiative efficiency of light-emitting materials Tim Gfroerer Davidson College, Davidson, NC - Funded by Research Corporation and the Petroleum Research.

100 µm Defect-related recombination and free-carrier diffusion near an isolated defect in GaAs Mac Read and Tim Gfroerer, Davidson College, Davidson, NC.

A-Si:H application to Solar Cells Jonathon Mitchell Semiconductors and Solar Cells.

Department of Aeronautics and Astronautics NCKU Nano and MEMS Technology LAB. 1 Chapter VIIIa Microcrystalline Silicon Solar Cells June 21, 2015June 21,

Design, Development, and Testing of a Transient Capacitance Spectroscopy System Presented by: Kiril Simov Special thanks to: Dr. Tim Gfroerer Department.

ECE685 Nanoelectronics – Semiconductor Devices Lecture given by Qiliang Li.

EE580 – Solar Cells Todd J. Kaiser Lecture 04 Semiconductor Materials Chapter 1 1Montana State University: Solar Cells Lecture 4: Semiconductor Materials.

Temperature-Dependent Transient Capacitance in InGaAs/InP-based Diodes Kiril Simov and Tim Gfroerer Davidson College Mark Wanlass NREL Supported by the.

Stretched exponential transport transients in GaP alloys for high efficiency solar cells Dan Hampton and Tim Gfroerer, Davidson College, Davidson, NC Mark.

Fig 2a: Illustration of macroscopic defects Diffusion lengths are calculated by the equation where μ is the mobility of electron with literature value.

Solar Cells, Sluggish Capacitance, and a Puzzling Observation Tim Gfroerer Davidson College, Davidson, NC with Mark Wanlass National Renewable Energy Lab,

ECE 4339 L. Trombetta ECE 4339: Physical Principles of Solid State Devices Len Trombetta Summer 2007 Chapter 9: Optoelectronic Devices.

When defects are present in a semiconductor, intermediate energy levels are formed allowing carriers to “step” down to lower energy levels and recombine.

TIM GFROERER, Davidson College Davidson, NC USA

Modeling defect level occupation for recombination statistics Adam Topaz and Tim Gfroerer Davidson College Mark Wanlass National Renewable Energy Lab Supported.

Basic Electronics By Asst Professor : Dhruba Shankar Ray For B.Sc. Electronics Ist Year 1.

NEEP 541 Ionization in Semiconductors - II Fall 2002 Jake Blanchard.

Solar Thermal Collector Solar Water heaters are one type of solar thermal collector. Water flows through black tubing in a black, insulated box with a.

Time-Resolved Photoluminescence Spectroscopy of InGaAs/InP Heterostructures* Colleen Gillespie and Tim Gfroerer, Davidson College, Davidson, NC Mark Wanlass,

While lattice-matched Ga 0.51 In 0.49 P on GaAs has the ideal bandgap for the top converter in triple- junction GaAs-based solar cells, more complex designs.

Note! The following is excerpted from a lecture found on-line. The original author is Professor Peter Y. Yu Department of Physics University of California.

Photocapacitance measurements on GaP alloys for high efficiency solar cells Dan Hampton and Tim Gfroerer, Davidson College, Davidson, NC Mark Wanlass,

Mapping free carrier diffusion in GaAs with radiative and heat- generating recombination Tim Gfroerer and Ryan Crum Davidson College, Davidson, NC with.

SILICON DETECTORS PART I Characteristics on semiconductors.

LIFETIMES AND DIFFUSION LENGTHS A STUDY IN SEMICONDUCTOR PHYSICS Ashley Finger and Dr. Tim Gfroerer Davidson College.

How does diffusion affect radiative efficiency measurements? Caroline Vaughan and Tim Gfroerer, Davidson College, Davidson, NC Mark Wanlass, National Renewable.

Using the model and algorithm shown to the right, we obtain the theoretical images above. These images, with A=4.2*10 7 cm 3 /s (defect pixel) and A=8.2*10.

Carrier Transport Phenomena And Measurement Chapter 5 26 February 2014

Looking Inside Hidden Excitons with THz Radiation Tim Gfroerer Davidson College Supported by the American Chemical Society – Petroleum Research Fund.

The review of modern physics has given us a description of nature. Waves are described with a wave equation. Particles are described with particle equations.

Photoluminescence and Photocurrent in a Blue LED Ben Stroup & Timothy Gfroerer, Davidson College, Davidson, NC Yong Zhang, University of North Carolina.

Modeling Radial Thermal Diffusion Ryan Phillips, Tim Gfroerer, and Peter Rossi Physics Department, Davidson College, Davidson, NC Abstract Thermal conduction.

Notes 27 February 2013.

Properties of metals Metals (75% of elements) Lustrous (reflect light)

Imaging and modeling diffusion to isolated defects in a GaAs/GaInP heterostructure Tim Gfroerer, Mac Read, and Caroline Vaughan, Davidson College, Davidson,

Defect-related trapping and recombination in metamorphic GaAs 0.72 P 0.28 grown on GaAs Tim Gfroerer, Peter Simov, and Brant West, Davidson College, Davidson,

How does diffusion affect radiative efficiency measurements? Caroline Vaughan and Tim Gfroerer, Davidson College, Davidson, NC Mark Wanlass, National Renewable.

Carrier generation and recombination A sudden increase in temperature increases the generation rate. An incident burst of photons increases the generation.

Thermally activated radiative efficiency enhancement in a GaAs/GaInP heterostructure* Brant West and Tim Gfroerer, Davidson College Mark Wanlass, National.

Intro to Semiconductors and p-n junction devices

Physics of Semiconductor Devices

Multiple choise questions related to lecture PV2

Organic Solar Cells: The Technology and the Future

Introduction to P-N diode

High Temperature Devices Based Upon Silicon Carbide

“Semiconductor Physics”

Outline Review Material Properties Band gap Absorption Coefficient Mobility.

Theory of the P-N junction

Photo Detectors.

SOLAR PANELS Photovoltaic cell Photovoltaic

Solar panels are pretty expensive, but they are good to save money on electricity. They take something from the sun and do something with it to make it.

Imaging and modeling diffusion to defects in GaAs Tim Gfroerer,Davidson College, Davidson, NC with Mark Wanlass, National Renewable Energy Lab, CO Diffusion.

Defect-related recombination near an isolated defect in GaAs Tim Gfroerer,Davidson College, Davidson, NC with Mark Wanlass, National Renewable Energy.

UNIT-III Direct and Indirect gap materials &

SOLAR PANELS Photovoltaic cell Photovoltaic

It was authored by Prof. Peter Y. Yu, Dept. of

Carrier Transport Phenomena And Measurement Chapters 5 and 6 22 and 25 February 2019.

Carrier Transport Phenomena And Measurement Chapters 5 and 6 13 and 15 February 2017.

Reciprocal capacitance transients

Recombination in low-bandgap InGaAs Tim Gfroerer Davidson College, Davidson, NC with Mark Wanlass National Renewable Energy Lab, CO ~ Supported by.

Organic Solar Cells: The Technology and the Future

Observation of an anomalous minority carrier trap in n-type InGaAs Tim Gfroerer and Kiril Simov Davidson College, USA Mark Wanlass National Renewable.

J. Peter Campbell and Tim Gfroerer Davidson College, Davidson, NC

Mac Read and Tim Gfroerer, Davidson College, Davidson, NC

Presentation transcript:

Photocapacitance measurements on GaP alloys for high efficiency solar cells Dan Hampton and Tim Gfroerer , Davidson College, Davidson, NC Mark Wanlass, National Renewable Energy Lab, Golden, CO Acknowledgements Davidson Research Initiative American Chemical Society Petroleum Research Fund Jeff Carapella for growing and processing test structures

Solar Cell Operation

Conduction Band Conduction Band Valence Band Valence Band Valence Band E=hc/λ Energy + Valence Band Valence Band Valence Band Valence Band

Conduction Band E=hc/λ Energy + Valence Band Valence Band

Conduction Band Conduction Band Conduction Band Conduction Band Energy Electron-Hole Pair + + Valence Band Valence Band

Conduction Band Conduction Band Conduction Band Conduction Band Band Edge Energy + + Valence Band Valence Band

Conduction Band Conduction Band Conduction Band Conduction Band Heat Conduction Band Conduction Band Conduction Band Conduction Band Band Edge Energy Ephoton – Band Gap Energy = Energy Lost + + Valence Band Valence Band

Defects

Conduction Band Conduction Band Valence Band Valence Band Valence Band Defect Levels Increasing Energy Trap Depth + + + + + + Valence Band Valence Band Valence Band Valence Band Hole

Conduction Band Conduction Band Valence Band Valence Band Valence Band + Defect Levels Defect Levels Defect Levels + Increasing Energy Trap Depth Capture + + + + + Valence Band Valence Band Valence Band Hole

Conduction Band Conduction Band Valence Band Valence Band Valence Band Defect Levels Defect Levels Defect Levels + Increasing Energy Escape Trap Depth + + + + + + Valence Band Valence Band Valence Band Hole

1 mm Picture of Device

N+ P - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Photocapacitance - - - - + + - - - - + - - - + - - - + N+ - P - - + - - + - - - - + - - + - - - - - + - + Depletion with bias

Depletion without bias Photocapacitance - - - - + + - - - - + - - - + - - - + N+ - P - - + - - + - - - - + + - - - - - - - + - + Depletion without bias

Depletion without bias Depletion Layer - - - - + - + - - - + - - - - + - + - - N+ - P - - + - - - - + - + - + - + - - - - - - + Depletion without bias

Depletion without bias Depletion Layer T = 77 K - - - - + - + - - - + - - - - + - + - - N+ - P - - + - - + - - - - + + - + - - - - - - + Depletion without bias

Depletion without bias Depletion Layer T = 77 K - - - - + + - - - - + - - - + - - - + N+ - P - - + - - + - - - - + - + - - - - - - + - + Depletion without bias

Conclusions Optical threshold escape energies are higher than thermal threshold energies → Configuration Dependent Traps GaAsP has a very large trap density, comparable to the density of dopants. This suggests zinc is contributing to the formation of the traps.