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looker22
Burkina Faso
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 Posted - 01/27/2008 : 01:11:14 AM
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Origin Version (Select Help-->About Origin): Origin 8 SR1
Operating System:Windows Vista
Hi there, I'm new to this wonderful program and i've been reading the help files and going through the videos however i still can't figure out how do i curve fit my data with Varshni's equation:
Eg(T)=Eg (0) T2/(T+)
Can anyone assist me with this pls. Thank you |
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Deanna
China
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Posted - 01/27/2008 : 8:49:10 PM
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Hi looker22,
Would you please tell us which are the parameters? and ? And what is Eg (0)?
Deanna
OriginLab Technical Services |
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looker22
Burkina Faso
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Posted - 01/31/2008 : 04:30:45 AM
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Hi sorry for the late reply Deanna. its supposed to be
Varshni equation:
Eg(T)=Eg(0) AT^2/(T+B)
A=alpha
B=Beta
A and B are my x n y values from my data, i think.
The radiative recombination coefficient is calculated from the absorption coefficient for band-to-band transitions, which we determine at different temperatures from photoluminescence spectra measured on planar high resistivity float zone silicon wafers.
Its to determine the temperature dependence of semiconductor band gaps.
http://homepage2.nifty.com/bussei_katsuaki/ApplPhysLett_58_2924.pdf
Edited by - looker22 on 01/31/2008 04:35:35 AM
Edited by - looker22 on 01/31/2008 04:41:00 AM
Edited by - looker22 on 01/31/2008 04:41:56 AM |
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larry_lan
China
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Posted - 02/01/2008 : 01:47:01 AM
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Hi:
You can use Origin's Curve Fitting tool to fit function like:
y = f( x; a, b, ...... )
where x is independent variable, y is dependent variable, and a, b, etc are fitting parameters.
I have no time to read through the paper, but I think this Varshni may be used to find out the relationship between temperature, T, and the energy, right? If so, your dependent variable should be Eg(T), independent variable should be T, Eg(0) is a constant, and A, B are fitting parameters. So you can define a function as follow:
In the Function edit box, the definition is:
double E0 = 1; // Define the constant;
ET = E0 - A*Tmp^2/(Tmp+B);
Thanks
Larry
OriginLab Technical Services |
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Kevinalvin
Malaysia
3 Posts |
Posted - 07/22/2013 : 10:03:19 PM
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Hi,can somene help me how to fit data to varshni equation (i'm originpro 8 user)
E(T)=E(0)-AT^2/(T+B)
E(T)is dependence variable
T is independence variable
A and B is fitting parameter (constant)
Thank you very much in advance
Kevin |
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snowli
USA
1379 Posts |
Posted - 07/23/2013 : 11:41:20 AM
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Hi Kevin,
Could you look at the screen shot in Larry_lan's post and try to create user-defined fitting function like that.
Did you met problems when fitting with the created fitting function?
BTW, in Fitting Function Organizer, please also set Parameter initial values such as the following will set initial A value to be 2, B to be 3.
InitialValues = 2,3(V)
If you don't set initial value, then in NLFit dialog, you need to go to Parameters tab and set initial values before click fit button.
Thanks, Snow |
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Kevinalvin
Malaysia
3 Posts |
Posted - 07/23/2013 : 9:59:02 PM
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Hi Snowli,,
Thank you very much..it is very helpful..
thanks again..
Kevin |
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Topic |
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How to Curve fit with Varshni's equation?