Intro to wxAMPS

Created & edited by Ryan

Last Revised on 01/2018 by Prof. Bayram.For errors/typos, please inform Prof. Bayram.

ECE 443: LEDs and Solar CellsUniversity of Illinois at Urbana-Champaign, IL, USA

Prof. Can Bayram, Associate Professor, Department of Electrical and Computer Engineering,University of Illinois at Urbana-Champaign, IL, USA EMAIL: cbayram@Illinois.eduWebpage: http://icorlab.ece.illinois.edu/

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AMPS (Analysis of Microelectronic and Photonic Structures) is a 1D simulation program with the ability to simulate photosensitive structures

AMPS was developed by Prof. Stephen J. Fonash (Pennsylvania State University)

wxAMPS is an improved version of AMPS, and was developed by Prof. Angus Rockett and Dr. Yiming Liu (UIUC) in collaboration with Nankai University of China

Software is open sourced– Available to download at

https://wiki.illinois.edu//wiki/display/solarcellsim/Simulation+Software

wxAMPS

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wxAMPS solves Poisson’s equation, including information about free carriers, traps, and dopant activation– Ability to use Fermi statistics in the case of degenerate material– Accounts for dopant levels and possibility of dopant bands in highly

doped material Also solves continuity equation for carriers

– Optical and thermal generation– Considers direct recombination and SRH recombonation

Solves device using finite element analysis, similar to BandEng and Crosslight

wxAMPS Physics

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We will make a p-i-n Solar cell using Si to explore the wxAMPS interface

Tutorial Overview

p-Si i-Si n-Si

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wxAMPS Interface Open wxAMPS by going to Start > Programs > wxAMPS First windows allows us to choose light conditions, create

material stack, simulate, and view resuts Similar to BandEng, all material parameters must be input

manually Select “Material” to start

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Name the first layer p-Si– Length = 0 um– Permitivity = 11.7– Eg = 1.12 eV– Affinity = 4.05 eV– Nc = 3.22 x 1019 cm-3

– Nv = 1.82 x 1019 cm-3

– Na = 1017 cm-3

– Must pick mobility un and up based on doping

• We will assume phosphorus and boron

– un = 688 cm2/V.s– up = 321 cm2/V.s– Save as ece498.dev

Material Menu

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Change to Optical tab– Absorption information for

common solar cell materials is provided

– Select “From File”– Open “p-Si.absx”

Material Menu

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Click “ADD” to make i-Si layer– Length = 0.1 um– Permitivity = 11.7– Eg = 1.12 eV– Affinity = 4.05 eV– Nc = 3.22 x 1019 cm-3

– Nv = 1.82 x 1019 cm-3

– un = 1414 cm2/V.s– up = 440 cm2/V.s

On Optical tab, load “i-Si.absx”

Material Menu

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Click “ADD” to make n-Si layer– Length = 1 um– Permitivity = 11.7– Eg = 1.12 eV– Affinity = 4.05 eV– Nc = 3.22 x 1019 cm-3

– Nv = 1.82 x 1019 cm-3

– Nd = 1 x 1017 cm-3

– un = 730 cm2/V.s– up = 314 cm2/V.s

On Optical tab, load “n-Si.absx”

Save as ece498.dev Click OK

Material Menu

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On Main Menu select “Ambient”– This menu allows us to set

light and biasing conditions, as well as run quantum efficiency tests

– Select “Load” next to Bias– Load wxAmps >

Dark0.8.vol – Click OK

Ambient Menu

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On Main Menu select “Run” After simulation completes, select “Results” to view results

Running Simulation

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Dark Results

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Return to the Ambient menu Check box for “Light On” Load FullAM1.5.spe from

spectrum folder Change bias to

Light0_1.5_2.vol Select OK Run the simulation

Light Results

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Light Results

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Return to the Ambient menu Uncheck box for “Light On” Check box for QE Load QE.cfg for Change bias to Only_QE.vol Select OK Run the simulation

Viewing Quantum Efficiency

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Viewing Quantum Efficiency

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Bias ranges are computed using .vol files

.vol file is a list of voltages that will be simulated in order to create a sweep

Example: Dark0.8.vol

Creating .vol files