Molecular and Condensed Matter Physics Laboratory (PHYS 4580) Photovoltaic Materials and Device Physics Laboratory (PHYS 6/7280)

Transcription

1 Molecular and Condensed Matter Phsics Laborator (PHYS 4580) Photovoltaic Materials and Device Phsics Laborator (PHYS 6/780) Instructors: Prof. Rand Ellingson, Prof. Mike Heben Teaching Assistant: TBD Course catalog descriptions: PHYS MOLECULAR AND CONDENSED MATTER LABORATORY [3 hours] Eperiments in molecular and condensed matter phsics. Measurements and analsis based on techniques such as film thickness and surface morpholog, X-ra diffraction, optical absorption, four-point probe and Hall measurements. One four-hour lab and one-hour lecture per week. Ma be offered as writing intensive (WAC section is - 071). Prerequisite: PHYS 330. PHYS 680/ PHOTOVOLTAIC MATERIALS AND DEVICE PHYSICS LABORATORY [3 hours] Fabrication and characterization of solar cell materials and devices, addressing materials science and phsics of substrate preparation, absorber and window deposition processes, metal contact formation, and measurement of phsical properties. One fourhour lab and one-hour lecture per week. Prerequisite: PHYS 6140/7140.

2 Molecular and Condensed Matter Phsics Laborator (PHYS 4580) Photovoltaic Materials and Device Phsics Laborator (PHYS 6/780) Things to discuss: Scheduling (lecture and lab) Lab Teams Lab Open Das/Times Lab Reports

3 Laborator Scheduling for 4580, 680 Arrange lab teams of 4 students. Each lab session is 4 hours. Additional lab time will be provided to enable students to repeat and/or correct measurements as necessar. Lab will generall be open Wed. and Thursda mid-da through the afternoon. Please contact us if the lab is locked during times ou need access.

4 Teaching Assistant: TBD Website: Overview Information Laborator location: R LabView used for instrument control (e.g., wavelength control in CM110 monochromator) and for data acquisition. Igor Pro (graphing and analsis software) Safet information. Eperiment overviews materials deposition, optical and electrical characterization (metals, transparent conductors, semiconductors), solar cell fabrication, test, and characterization.

5 Overview Information (continued) Lock-in detection (w/ fied-frequenc signal modulation), Analog-to-Digital Conversion (ADC, and generall, Data Acquisition (DAQ)), data analsis and reconciliation. Units importance of proper handling of units, and use of SI units wherever possible (provide conversion information). Introduction to error analsis and error propagation.

6 A. Eperimental Practices B. Graphing and Analsis with Igor Pro C. Intellectual Honest Week of Aug. 0, 01 Molecular and Condensed Matter Lab (Phsics 4580) PV Materials and Device Phsics Lab (PHYS 6/780) The Universit of Toledo Instructors: R. Ellingson, M. Heben

7 Eperimental Methods and Practices

8 Ke Elements of the Scientific Method Scientific method: ask and answer scientific questions through eperiment and observation. The steps of the scientific method are to: 1. Define the question. Gather information and resources (observe) 3. Form hpothesis 4. Perform eperiment and collect data 5. Analze data 6. Interpret data and draw conclusions that serve as a starting point for new hpothesis 7. Publish results 8. Retest (frequentl done b other scientists) The iterative ccle inherent in this step-b-step methodolog goes from point 3 to 6 back to 3 again. It is important for our eperiment to be a fair test. A "fair test" occurs when ou change onl one factor (variable) and keep all other conditions the same.

9 Thoughts on the Scientific Method Ibn al-hatham (Alhazen, ), pointed out the emphasis on seeking truth: Truth is sought for its own sake. And those who are engaged upon the quest for anthing for its own sake are not interested in other things. Finding the truth is difficult, and the road to it is rough. According to William Whewell ( ), "invention, sagacit, genius" are required at ever step in scientific method. It is not enough to base scientific method on eperience alone; multiple steps are needed in scientific method, ranging from our eperience to our imagination, back and forth.

10 Scientific Method: Beliefs and Biases Eadweard Mubridge's ( ) studies of a horse galloping The Epsom Derb (181) b Géricault, Jean Louis Théodore. Oil on canvas.

11 Igor Pro 6.1

12 Igor Pro 6.1 (

13 Igor Pro information (please note) Download the IgorPro Demo (available for either Mac or Windows), and use this information for the S/N and the Activation Ke. Serial Number: 5003 Activation Ke:

14 Error (uncertaint) analsis f z, f f z,, 1,, f f z For uncorrelated errors: See also:

15 4 4 s r C r s C A r r s C C s r A r s Cr r C s Cr C A r s Cr C s r A Where C is count rate, r is the distance to the detector, and s is the radius of the detector. In quadrature, if these errors are uncorrelated: Error (uncertaint) analsis eample using Activit of 41 Am source

16 Error (uncertaint) analsis multiple value r.m.s. approach Another approach to evaluating the uncertaint relies on a straightforward calculation of the root mean square and the standard deviation. In the case of our Activit measurements, ou could compute the RMS value as well as the SD. You should still assess our uncertaint through error propagation, as the uncertaint ma ver well eceed the SD. Definition of the root mean square from Wikipedia: the square root of the arithmetic mean (average) of the squares of the original values In the case of a set of n values 1,, n, the RMS value is given b: rms 1 n n The standard deviation is given as follows, where there are N values and is the arithmetic mean: 1 N i N 1 i

17 Lab Reports: Ensure individual reports represents our own words and understanding, even when data is shared. Show what ou have learned describe the eperiment (background, what is measured, important steps, how things fit together, origins and magnitude of the uncertainties); Label our graphs carefull ensure that the reader knows what is graphed. Include units on each ais label, and on other quantities (refer to sllabus for more detailed info). Internet age avoid plagiarism: understand what ou read, know the points ou want to make, and restate the ideas in our own words. You ll learn more this wa, and avoid potentiall big problems.