# What is Thin films: Definition and 57 Discussions

A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many applications. A familiar example is the household mirror, which typically has a thin metal coating on the back of a sheet of glass to form a reflective interface. The process of silvering was once commonly used to produce mirrors, while more recently the metal layer is deposited using techniques such as sputtering. Advances in thin film deposition techniques during the 20th century have enabled a wide range of technological breakthroughs in areas such as magnetic recording media, electronic semiconductor devices, Integrated passive devices, LEDs, optical coatings (such as antireflective coatings), hard coatings on cutting tools, and for both energy generation (e.g. thin-film solar cells) and storage (thin-film batteries). It is also being applied to pharmaceuticals, via thin-film drug delivery. A stack of thin films is called a multilayer.
In addition to their applied interest, thin films play an important role in the development and study of materials with new and unique properties. Examples include multiferroic materials, and superlattices that allow the study of quantum phenomena.

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1. ### Solid State Researching Gold Thin Films: Electrical & Optical Properties

Hi Physics folks,I am currently collecting resources for my senior seminar project at my university and would like to ask if anyone has any good references for gold thin films. I am planning on focusing primarily on the electrical and optical properties of gold thin films. I appreciate any...
2. ### Interference of light in thin films

Phase difference is $\phi=\frac{2pi}{\lambda}* \Delta+\pi$ Phase difference, max: $\Delta \phi=2pim=\frac{2pi}{\lamda_{max}}*2nd$ Phase difference, max: $\Delta \phi=2pim=\frac{2pi}{\lamda_{min}}*2nd+pi$ Flim thickness: $d=100nm$ Set the equations equal to each other i got a d=-100nm which...
3. ### Interference in thin films; confusion regarding geometry

Instead of talking about the simple of case of reflection interference due to a single film, this book starts off with two films with an angled air wedge between them. They talk about the "thickness", ##t##, of the wedge, but this thickness varies along the length of the films (Figure 35.`12)...
4. ### Metal thin film adhesion, Au-Si deposition

What protocol should I use to get a good stable 100nm Au adhesion onto a Si substrate using electron beam evaporation? I've heard talk of primer layers of either Cr or Ti at around 5nm thickness, as the typical way to do it. Which material should I choose? What the advantages or disadvantages...
5. ### Finding the Minimum Thickness for Destructive Interference in Thin Films

Homework Statement A uniform film of TiO2, 1036 nm thick and having index of refraction 2.62, is spread uniformly over the surface of crown glass of refractive index 1.52. Light of wavelength 515 nm falls at normal incidence onto the film from air. You want to increase the thickness of this...
6. ### Gas adsorption for (BET) surface area of graphene oxide based thin films

I am using a Micromeretics ASAP2020 machine. The sample is ~25mg of reduced graphene oxide based film. The problem is I am getting adsorption isotherms showing negative volumes of adsorbate (N2) entering the tube as P/P0 increases. The sample was degassed prior to testing at 250°C for 3...
7. ### Thin film interference - why thin, exactly?

Hi, in every explanation of thin film interference I came across, little or nothing is said as to why the layer of transparent material creating the effect should be thin. What would go wrong if that is not the case? I'm asking because it seems to me that, in principle, the mathematic...
8. ### Nonreflective Coating and Emission Relation?

Hi all, I've been able to find the answers to most of my questions in these forums, but this time I was not able to. So here goes my first post: I've been learning about thin film interference, and it all makes sense to me except for the correlation between destructive interference caused by...
9. ### Interference in Thin Films: Grade 12 Optics Review

Homework Statement Would you see the same thin film interference pattern in a film of soap surrounded by air and a film of soap on glass? Why or why not? Homework Equations None The Attempt at a Solution Yes, you would see the same thin film interference pattern in a film of soap surrounded...
10. ### What is the Explanation for the Interference Pattern in Thin Soap Films?

Homework Statement Green light is shone onto two soap films. An observer looking down at the soap films sees that soap film X appears uniformly green while soap film Y has green and black bands. If air is the medium on either side of the soap film, the best explanation of this pattern is...
11. ### Thin films: reflection between glass plates

Homework Statement Two parallel glass plates of index of refraction n are separated by an air film of thickness d. Light of wavelength λ in air, normally incident on the plates, is intensified on reflection when, for some integer m a) 2d=mλ b) 2d=mλ/n c) 2d=mnλ d) 2d=(m+1/2)λ e) 2d=mλ/2...
12. ### How Does Soap Bubble Thickness Affect Light Interference?

Homework Statement (a) Calculate the minimum thickness of a soap bubble film that results in constructive interference in the reflected light if the film is illuminated with light whose wavelength in free space is λ=600nm. The index of refraction of the soap film is 1.33. (b) What is the film...
13. ### Why isn't my laminator sticking PET thin films together at high temperatures?

Hi all, I am trying to laminate two ITO-coated PET thin films together with heating (I believe the temperature generated by my laminator is above 80 Celsius degree), but they did not stick together even a little bit. I have checked online for a few articles, laminating PET with heating (above...
14. ### Simulation Inhomogeneous Compound Semiconductor Thin Films

I'm not good at English. I'm a undergraduate student. I'm interested in this research. I'm interested the simulation part but I don't know how to start. Please guiding me how to simulate method or program did they use on paper. " A Theoretical Study on Van Der Pauw Measurement Values of...
15. ### Calculating Thin Film Thickness Using Interference Patterns

Homework Statement A thin film with an index of refraction of 1.60 is placed in one of the beams of a Michelson interferometer. If this causes a shift of 8 bright fringes in the pattern produced by light of wavelength 580 nm, what is the thickness of the film?1.5 µm 2.9 µm 3.9 µm 7.7 µm 16...
16. ### Factors affecting the size of ZnO thin films (by spray pyrolysis)

Good day guys, aside solution concentration and depositing time, what are the factors affecting the size of the ZnO thin films deposited by spray pyrolysis. Also please include the articles or links for citation thanks!
17. ### Criteria for choosing a substrate for thin films

Hi guys!, i want to know what are the criteria in choosing a substrate to deposit thin films, like what are the physical and chemical properties of the substrate to be compatible in depositing thin films?
18. ### Silicon wafer as substrate in Zinc oxide thin films

Good day, many articles used sillicon wafer as substrate over others (like:platinum, glass, sapphire and etc) to grow Zinc oxide thin films, but I'm don't know the real reason they choose silicon wafer as substrate compare to others. so I'm asking what are the advantages of using Silicon wafers...
19. ### Interference pattern for thin films

Homework Statement A parallel beam of light of wavelength ##\lambda## is incident normally on a thin polymer film with air on both sides. If the film has a refractive index ##n>1##, then, for what value of the thickness, can second order bright fringes be observed in reflection? Homework...
20. ### Interference in Thin Films: Determining SiO2 Layer Thickness Using a Wedge Setup

Homework Statement In order to decide the thickness of a SiO2 layer(n=1.5) on Si, a wedge is prepared as shown in the picture. A total of 7 DARK fringes was observed, when light of wavelength 589nm shines prependicularly on the wedge. It is known that light reflected from the Si/SiO2 surface...
21. ### Reflection from Thin Films Plot

Homework Statement Here is a plot of Reflectance vs Wavelength from a multilayer thin film stack of alternating high and low refractive indices: I want plot this in Matlab, but what equation was used for this plot? The diagram is from my textbook, there are many like it online but...
22. ### Optimizing Thin Film Coatings for Minimum Reflection: A Practical Guide

Homework Statement Optical lenses (n=1.40) in cameras are coated with a thin film of magnesium fluoride (n=1.38) to reduce reflections. What minimum thickness is required to give minimum reflection at a wavelength of 550 nm? Homework Equations 2nt = (lamda)/2 The Attempt at a...
23. ### Index of refraction Thin Films

Homework Statement The diagram shows light incident from above on a film of thickness d. Each of the three materials in the figure can be chosen to be air, with index of refraction n=1.00, water, with index n=1.33, or glass, with index n=1.50. Under which of the following conditions will the...
24. ### Interference patterns in thin films

Why the interference patterns are separated when there are many light beams transmit through the film? Thanks!
25. ### How Can I Obtain Thin Films for DSC Analyses of P3HT PCBM?

Hi I want to do DSC analyses of P3HT PCBM film (active layer of the solar cell), but I'm not sure how to obtain that thin layer separately from the substrate. You know that the containers for DSC are very small. I tried with drop casting but I think it's not the best way because I don't have...
26. ### QED & Thin Films: Wave Interference or Probability?

I've been reading a bit around Quantum Electrodynamics (QED) which says that when you shine monochromatic light onto a thin film, the fact of whether it produces a dark or bright band is purely a probability function. It seems to say you use Feynman arrows, one for the first surface and one for...
27. ### What are the properties and applications of ferromagnetic thin films?

Hi, I am doing my PG. To select a topic for my mini project, I select the topic "Ferromagnetic thin films" Probably I will be covering it's properties, fabrication and applications at some basic level. So what is the problem is I have no one to guide me here as I am far away from the...
28. ### What is the minimum thickness required for ferromagnetism in thin films?

Hi, I am doing my PG. To select a topic for my mini project, I select the topic "Ferromagnetic thin films" Probably I will be covering it's properties, fabrication and applications at some basic level. So what is the problem is I have no one to guide me here as I am far away from the college...
29. ### Etching SnO2 Thin Films: Advice Needed

Please, give me some advices on how to etch SnO2 thin films. For wet etching, I tried HCl (5%), NH3Cl, and HF. They seem to not etch SnO2 or the time I put the SnO2 in the solution was too short (<5 mins). I used RIE with CHF3/Ar to etch SnO2. The RIE worked but the etching rate was so slow...
30. ### Understanding Voltage Decay in Semiconductor Thin Films

Hello! I am trying to carry out wavelength depended photoconductivity experiment to a semiconductor thin film material. I use keithley 2400 sourcemeter. I do apply voltage to the sample under pressure and read the current. My problem is when i apply a constant voltage to the sample i see that...
31. ### Good Information on Thin Films

any one have good information about thin films
32. ### Interference in Thin Films, figuring out the phases

Homework Statement I don't have a question on a specific problem, I am more caught up in the determination of the phases- I'll give a general problem to use as an example: In Fig. 35-41, light is incident perpendicularly on a thin layer of material 2 that lies between (thicker) materials 1...
33. ### Crystallite size in thin films

Hi, just a question for about a doubt I have regarding the xrd analysis, maybe too trivial for experts...I have estimated the crystallite size in a thin films (my films have 100nm thickness), using rietveld refinement programs. I have always thought that in this way I estimated the size of the...
34. ### Simulating Diffusivity in Electroceramic Thin Films

I'm doing electroceramic thin films for DRA applications. I'm realized, it is hard to observe diffusivity in film layer since the thickness is in nanosize, even by AFM and SEM only shows grains size and distribution. So I'm making basic assumption growth of the grain represent diffusivity as...
35. ### Thin films interference hard problem

Homework Statement A 360 nm thick oil film floats on the surface of the water. The indices of refraction of the oil and the water are 1.50 and 1.33, respectively. The surface of the oil is illuminated from above at normal incidence with white light. The two wavelengths of light in the 400 nm...
36. ### Solving Thin Films Interference Problem with Oil and Water | 360nm Thickness

Homework Statement A 360 nm thick oil film floats on the surface of the water. The indices of refraction of the oil and the water are 1.50 and 1.33, respectively. The surface of the oil is illuminated from above at normal incidence with white light. The two wavelengths of light in the 400 nm...
37. ### HELP with Thin Films Questions

I would really appreciate if anyone can help me with these 2 questions! I really need help with my homework assignment and I don't have a good materials background... 1. Au has been found to be a very good anode electrode for OLEDs (see, for example, M.G. Helander, et al. Adv. Mater. 22...
38. ### Is 2t a Rough Estimate of Wavelength in Thin Film Interference?

Hi guys, i have problem with Interference in Thin Films, i tried worked the solution not sure it is correct. Hope someone can help me check? Also there is some part on the topic i don't quite follow, 2t is the extra distance traveled inside the film, then is 2t is also rough estimate of...
39. ### How to Determine Minimum Thickness for Dark and Bright Spots in Soap Films?

Homework Statement Light of wavelength 580 nm strikes a soap film (n=1.33), which is surrounded by air. What is the minimum thickness needed to produce a) dark spot? b) bright spot? Homework Equations n1/n2=wavelength 2 / wavelength 1 2t = m (wavelength) <-- dark 2t = (m + 1/2)...
40. ### Iinterference in thin films due to reflected light

Homework Statement dear revered members, please find the attached image for the topic interference in thin films due to relection. Homework Equations my questions are 1) angle between the incident ray or reflected ray or refracted ray is called angle of incidence, angle of reflection...
41. ### Find Optimal Wavelength for Thin Film Camera Lens Coated with Magnesium Fluoride

Homework Statement A camera lens (n = 1.90) is coated with a thin film of magnesium fluoride (n = 1.40) of thickness 90.0 nm. What wavelength in the visible spectrum is most strongly transmitted through the film? Homework Equations ? The Attempt at a Solution I have no idea...
42. ### What Wavelengths Are Missing in the Reflected Light from a Thin Film Coating?

Homework Statement A coating of film n=1.37 on glass slabs (n=1.6) is 8.45X10^-5 cm thick.If white light is incident normally, which visible wavelengths are missing in the reflected light? White light containing wavelengths from 400 to 700 nm. Homework Equations The Attempt at a...
43. ### Optics / interference in thin films

Homework Statement A soap bubble n=1.33 is floating in air. If the thickness of the bubble wall is 115 nm, what is the wavelength of the light that is most strongly reflected Homework Equations 2nt=(m+0.5)(lambda) The Attempt at a Solution most strongly reflected = constructive...
44. ### Optical Transmission through thin films.

Hello everyone. I have some zirconium that is coated with 1nm of Ni. Now, here's the problem: I don't know if the coating is actually 1nm and have to find out. I don't have access to our AFM today, so I can't use that. But I do have light transmission data from the sample. i.e. I know...
45. ### Interference in thin films: why thin?

Hi, When you have interference in thin films, why does the film has to be thin? Why doesn't it work with "thick" films? In my textbook they don't explain this constraint... Thank you.
46. ### Thin Films with consideration to Amplitude

Homework Statement Consider the case of a film of thickness \lambda/4 with an index nf where nf<ng=1.5 that is applied to a glass surface. For minimum reflection the reflected rays r1 and r2 must cancel each other out. Since r1 and r2 both reflect fast to slow, they are in phase on...
47. ### Interference from Thin Films: What Happens to Wavelengths in Different Media?

Homework Statement Light of wavelength x, in air, is incident in air on a film of oil with index of refraction n_oil = 1.45. The film of oil has thickness L, and is spread on glass with an index of refraction n_glass = 1.50. The wavelength of the light in oil will be _____ than the wavelength...
48. ### What is the condition for destructive interference in thin films?

Homework Statement Light of wavelength \lambda strikes a pane of glass of thickness T and refractice index n, as shown in figure(I attached a diagram I made). Part of the beam is reflected off the upper surface of the glass, and part is transmitted and then reflected off the lower surface of...
49. ### [thin films] (Macleod's) phase-shift upon reflection

Folks, I'm reading the 3rd edition of Thin Film Optical Filters by Macleod, and I've derived his expression for phase shift upon reflection (page 45). Finally, it lead me to a question. Any help is highly appreciated! \rm E_i + E_r = E_t \qquad (1) \rm H_i - H_r = H_t \qquad (2)...
50. ### Is My Calculation for Film Thickness Using Interference Method Accurate?

After I read many articles about measuring film thickness by interference method. I tried to calculate flow that papers but I can't the equation is d= (y1*y2)/(2*(n1y2-n2y1)) for an easy I approximate n1 =n2 so d= (y1*y2)/(2*n(y2-y1)) y1 = 350 nm y2 = 380 nm n =...