Sunday 29 November 2015

Nov 29: Story of a cover image, "Reconstruction of the first ALE experiment"

November 29, 2014, it was exactly 40 years since the filing of the first patent on Atomic Layer Epitaxy by Suntola and Antson (FIN 52359). To celebrate this, the Finnish Centre of Excellence on Atomic Layer Deposition (ALDCoE) released the material of the exhibition "40 Years of ALD in Finland - Photos, Stories" (FinALD40) in the internet. Originally, this exhibition had been created for the Baltic ALD 2014 conference in Helsinki, May 12-13, 2014.

Today, one year later, I want to tell you the story behind the cover image of the internet release of the the FinALD40 exhibition material. The cover image is called: "reconstruction of the first ALE experiment" and is shown in the next figure.

"Reconstruction of the first ALE experiment". © Riikka Puurunen 2014

In the FinALD40 exhibition material (2nd page, bottom) the image is described as follows:
"Reconstruction of the first ALE experiment in 1974. Tuomo Suntola standing next to the ALE reactor, observing the appearance of purple interference colour in the growing film. The scheme has been modified from a figure in the story of Tuomo Suntola’s ALE in Short. The silhouette photograph has been taken by Riikka Puurunen of Tuomo Suntola on August 23, 2014 - almost exactly 40 years after the first ALE experiment was made." 
Indeed, I have created this image together with Tuomo Suntola, the Finnish inventor of ALD. But: why? And: how?

It all started, when the "Suntola ALE Essay", which I wrote in close collaboration with Suntola, had been accepted for publication in the CVD journal. I was invited to create a cover image for the CVD issue in which the essay would be published. Many scientists consider having such covers of their work an achievement as such. With Suntola we thought that this was an attractive idea: it would be like "the point on the i", as we say in Finnish. (Maybe people say similarly in other languages, too?) We went on with the idea of creating a cover image.

How should the cover image look like? Sometimes, one can just choose a suitable image from the materials in the accepted manuscript, perhaps after making small modifications. Other times, completely new images are created. Some even design cover images as part of their profession. I have experience of creating a cover image related to a previous large ALD review that we wrote together with Miikkulainen, Leskelä and Ritala, published in Journal of Applied Physics (JAP). The image below shows how that cover image looked like: it is simply a specially lit close-up photograph of a printed version of the "Periodic table of ALD", which summarizes the ALD processes developed for different elements. (This periodic table summary I had first created for my 2005 JAP review, and we updated it for the 2013 JAP review. )

Cover  of Journal of Applied Physics, Vol. 113, Year 2013, Art. 121301, featuring a photograph by Riikka Puurunen.

Photographs have worked well earlier. Maybe we could again create something with photos? A collage of many old photos together? Or create something completely new? Together with Suntola we exchanged ideas and made sketches, but nothing seemed really really good ... until I sent him an example of a silhouette photograph of myself, taken earlier (silhouettes have been some kind of a hobby for me for quite some time). In a return email, Suntola sent me back a sketch, where the silhouette was looking down through the viewing window of the scheme of the ALE reactor. The person was watching the growth proceed, in the first ALE reactor. Good idea, but wrong person! We needed a silhouette of Tuomo Suntola himself.

On one Saturday afternoon (August 23, 2014, to be specific), I took my photography gear and went to Suntola's home for a photography session. One flash with remote triggering was used for taking the photo (thanks to Mr. Strobist for teaching me flash photography). We tried different backgrounds, settling with simple white bed linen. Self-evidently, it would be a silhouette from the side. We tried a few different poses; the final one, taking a pen in the hand as if making notes, was Suntola's idea. This is similar as what he did during the very first ALE experiment: watching through the in situ viewing window of the reactor, waiting to see purple colour appearing, and noting the time when this occurs, to be able to calculate the thickness deposited in a time unit. (The graph shown at the right side of Figure 2 in the Suntola ALE story, shows the results of this observation.) This would make an excellent reconstruction of the first ALE experiment.

Once we had a suitable photograph, it was straightforward to edit the image and combine the photograph with the reactor scheme. The reactor scheme itself was resized and stylised for the cover format. The colours in the scheme were tuned to add to the reconstruction: blue and yellow reminded one of elemental zinc and sulphur; red-orange of heated surfaces; light yellow and purple of the original light and the periodically purple reflected light. The position of the reflected purple light line was adjusted so that the reflection comes from the bottom of the glass substrate, as this is where film growth took place in the first experiment and reactor. The final choice of tints for the colours were inspired by the Finnish artist Tove Jansson's colour schemes.

So, we had created a cover illustration for the CVD journal. But: alas, it was never used as such. Another publication came in the way: an article about 40 years of ALD in the Finnish Kemia-lehti.

Kemia-Lehti ("Chemistry Journal") is a magazine aimed for chemistry professionals. During summer-fall 2014, Kemia-lehti had gotten interested in the FinALD40 exhibition, which at that time was exhibited at VTT Technical Research Centre of Finland at the Micronova building, in Espoo, Finland. On the basis of visiting the exhibition, and also through interviewing Suntola directly, journalist Maija Pohjakallio wrote a very nice article on the history of ALD, published in Issue 7/2014 of Kemia-lehti, mid-November.

For this article, Maija Pohjakallio requested image material from the FinALD40 exhibition. I gave her also the "CVD cover image" to use. I knew that there was a risk that CVD would no more accept it as the cover image, as it would no more be completely new, but I judged that the Finnish chemistry professionals deserved to see the image in this Kemia-lehti article. ALD is highly respected in Finland as a Finnish invention, and Tuomo Suntola was also one of the 100 noteworthy Finn chosen for the recent book: "Suomalaisia tieteen huipulla: 100 tieteen ja teknologian saavutusta (my translation of the title: Finns at the top of science: 100 achievements of science and technology)."* To Finnish chemistry professionals, the image might have a higher value than to the international audience. The figure shows part of Pohjakallio's article.

Screen capture from Kemia-lehti,  Issue 7/2014, article "Neljä vuosikymmentä ALD-kalvoja: Tuomo Suntolan idea mullisti pinnoitusteknologian", by Maija Pohjakallio. 

Indeed, it happened, my fear came true. Because the image had now already been published, CVD no more wanted to consider the image as their cover. We did not get the cover of CVD --- but we did get a great cover for the FinALD40 exhibition's electronic material.

Frontpage of the internet release of the exhibition material by ALDCoE "40 Years of ALD in Finland - Photos, Stories"(FinALD40), containing the image "reconstruction of the first ALE experiment". Exhibition material was published in the internet November 29, 2014, exactly forty years after the first patent of ALE was filed.
*) "Suomalaisia tieteen huipulla: 100 tieteen ja teknologian saavutusta", Eds. Tapio Markkanen, Allan Tiitta and Paula Havaste, Copyright Gaudeamus Oy, printed in Tallinna Raamatutrükikoja OÜ, Tallinn, 2014, 250 p. ISBN 978-952-495-328-3. The chapter on Suntola and ALD was written by Professor Markku Leskelä from University of Helsinki.

Virtual Project on the History of ALD (VPHA) - in atmosphere of Openness, Respect, and Trust

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