Helmholtz Zentrum Berlin

#HZBzlog

hzbEMIL • Watching the Secret Lives of Atoms

Egg, spoon, vacuum

Updates

  • authored 4 years ago:

    The transferbox has landed in Adlershof!

    … finally after several attempts, we succeeded in transferring a CIGSe sample from the growth chamber in Wannsee to Adlershof without breaking the vacuum.The as-grown sample was analysed by photoelectron spectroscopy (PES) in the CISSY system, a dedicated surface analysis and preparation system which is located at BESSY II on the Wilhelm-Conrad-Röntgen Campus and which is suitable for synchrotron …

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    comments
    • authored 4 years ago:

      It has its peaks but in the end it all goes down. Good job measuring the curve of life.

      No, seriously - congratulations and good luck for the future! Just reading things like "breaking the vacuum" and "carbon contamination" brought back some bad memories...

  • authored 4 years ago:

    Proof of concept: The vacuum transfer in pictures (II)

    After lunch and about two hours of waiting for the deposition process to end, the actual transfer of the sample can begin.Again, the only way to move anything inside the machinery is with the transfer rods.Then it's time for Karsten Prietzel's newly designed gripper to pick up the fresh sample.At this point, it looks like an extra arm would be nice...Somehow, they manage. Step one - complete.Now …

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  • authored 4 years ago:

    Proof of concept: The vacuum transfer in pictures (I)

    The first complete test run of the new vacuum transfer unit had had to be postponed a number of times, but yesterday Wolfram Calvet and Karsten Prietzel finally got their chance - and they used it.Here they maneuver the transfer unit into the lab to connect it to the deposition unit where the chalcopyrite absorbers are made. As in most labs, space is a limited resource, and the long transfer rods …

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  • authored 4 years ago:

    The sample

    Here connecting the vacuum unit to the processing machine. Particle filter masks have to be worn to …

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    comments
    • authored 4 years ago:

      Selenium is essential for the human being - but only in a special dose. If the dose of selenium is too high, it can irritate the respiratory system. Over a long period of time an overdose can damage lung, liver and kidneys.

    • authored 4 years ago:

      Not a clue. I would think so, otherwise: why the masks? But what exactly Selen does to you - I have no idea.

      Anybody else around here who can help us with this?

    • authored 4 years ago:

      Nice picture! What would happen, if the scientist breathes some selen atoms? Is it dangerous?

  • authored 4 years ago:

    The vacuum transfer unit

    Kerstin just sent some pics from the processing in the lab. I am starting to get a notion of just …

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  • authored 4 years ago:

    #transfer: The road to Adlershof

    It doesn't look that far on the map. But the fastest way is to go half way back into Berlin, and …

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  • authored 4 years ago:

    Today: 37 kilometres without oxygen

    The day has come at last. Today, Wolfram Calvet and his team will perform their first complete test run of the new vacuum based transfer unit, that will allow them to bring freshly processed samples of chalcopyrite absorber from the processing site in Wannsee to the CISSY-facility in Adlershof for analysis without oxygen or other contamination.All procedures have been tested – and tested again – …

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  • authored 4 years ago:

    Hi plan, meet reality. Hello reality, meet plan.

    It all looks fairly straightforward and simple:Until you enter the real world:This is the setup to get the sample out of the processing machine where it is made and into the transfer chamber on the cart. Since everything is very rigid (so it can withstand the vacuum) and squeaky clean (literally - everything that is not the sample has to go out, including all kinds of greases etc.) the whole setup …

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  • authored 4 years ago:

    Heute stellen wir da

    Heute stellen wir das HZBzlog auf #lndw2014 vor. Interessante Gespräche über unsichtbare …

  • authored 4 years ago:

    On patience...

    It is really a pity that the appointed day could not be used for the first transfer of a real CIGSe absorber from Wannsee to Adlershof due to technical problems. However, we have to be patient and hope for the next chance. This case demonstrates how research often goes and is typical for it, two steps forth and one step back or in other words “The progress is a slug…”

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  • authored 4 years ago:

    Während der Vakuumkoffer wartet - A short intermission

    Es gab ja noch andere Koffer in Berlin…

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  • authored 4 years ago:

    In-situ Transfer verschoben, wegen "Dreck"...

    Am Freitag musste Ingenieur Karsten Prietzel leider folgendes vermelden:"Hallo Frau Hoppenhaus,ich habe leider wieder schlechte Nachrichten. Beim heutigen Prozess hat eine der Prozesskontrollen nicht funktioniert. Beim Ausheizen der Anlage muss sich „Dreck“ gelöst haben und dann auf den Sichtflansch gefallen sein. Jedenfalls müssen wir die Anlage am Montag nochmal öffnen. Der Vakuumtransport …

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  • authored 4 years ago:

    This is how THIN thin films are!

    We are talking a lot about thin film solar cells. This little video compares common silicon layers …

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  • authored 4 years ago:

    In-situ transfer: new date

    Die Dinge entwickeln sich! Karsten Prietzel hatte gestern Abend gute Nachrichten:"Die Indium-Quelle ist eingebaut. Es fehlt nur noch die Abdeckung („Shutter“), die wir heute anbauen. Der Shutter dient dazu, dass wenn die Quelle die Verdampfungstemperatur des Materials erreicht hat (in diesem Fall Indium), kein Material aus der Quelle dampfen kann – Wir wollen ja stets definierte Materialmengen auf …

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  • authored 4 years ago:

    The adapter - custom-made

    The precious 'last piece in the puzzle' for the in-situ transfer was built by Henry Plötz who was …

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  • authored 4 years ago:

    The precious adapter

    Doesn't look like much. But then, they never do...

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  • authored 4 years ago:

    Der Adapter

    Für den Ingenieur Karsten Prietzel ist der Aufbau des Vakuumtransportkoffers das erste eigene große …

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  • authored 4 years ago:

    “God made the bulk...

    “... the surface was invented by the devil!” (Wolfgang Pauli, German theoretician, Nobel prize in physics 1945)This is exactly the situation we are currently facing with thin film solar cells based on the chalcopyrite material Cu(In,Ga)Se2. But before going into this, a short summary on the chalcopyrite story is necessary. About thirty years ago, Si and GaAs based solar cells were already …

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    comments
    • authored 4 years ago:

      Thank you for this nice quote of Pauli. Now I begin to grasp what makes physics of thin film solar cells so difficult to grasp: Since they are really thin, they consist of little bulk and lots and lots of surface and interfaces.

  • authored 4 years ago:

    Change of plans: No transfer today

    After months of preparation, the in-situ transfer apparatus is now ready to be tested. But the first complete run that will link the absorber processing site in Wannsee with the CISSY-station in Adlershof - originally scheduled for today - had to be postponed on short notice.The reason: A defective Indium source. The samples to be transferred are CIGS solar cells, i.e. they need Copper, Indium, …

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  • authored 4 years ago:

    Solar cell materials – an overview

    The search for new materials in solar cells is one of the biggest and most hard-fought topics that challenges scientists around the world, including the physicists and engineers at HZB. Headlines praising ever higher degrees of efficiency and ever thinner absorber layers are published with quite a reliable regularity. As this is such a vivid and innovative sector, it is sometimes hard to maintain …

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  • authored 4 years ago:

    Custom-made gripper

    Part of the problem of the in-situ transfer from one machine (and location) to another is that the …

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  • authored 4 years ago:

    Chalcopyrites across town

    Just in time for easter, Wolfram Calvet and Karsten Prietzel of the wider EMIL-team are embarking on their own version of an egg and spoon race. Early next week, they will be running the first in-situ transfer of a chalcopyrite thin film sample from the processing machine in Wannsee to the the CISSY diagnostic facility in Adlershof, on the other side of town.This may not sound like too big a deal, …

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    comments
    • authored 4 years ago:

      Thanks, Iver Lauermann, for putting things into perspective. I am still new to all this and I greatly appreciate background information from people who have known the field for years. Please keep it coming!

    • authored 4 years ago:

      Well, I think it would not be fair to some colleagues to leave this post uncommented because this one sentence is not quite right: "With this transfer, it will - for the very first time - be possible to use photoelectron spectroscopy (PES) on the still quite mysterious surfaces of chalcopyrites without any oxygen or other contamination." In fact, back in the nineties there was a system at the IPE (Institut für Physikalische Elektronik, http://www.ipe.uni-stuttgart.de) in Stuttgart that did exactly that. There, chalcopyrites could be deposited and analysed in the same machine without even the need for UHV transfer. Much of what we know today about this material and its surface was published then, e.g. by such well known researchers like Hans-Werner Schock, who was later director of HZB institute E-IT. So why then do we set up another system to repeat these measurements? The answer is that the chalcopyrite material that is made today can lead to solar cells with an efficiency of more than 20% and that this material is different from that back in the nineties with much lower device efficiency. So we need to understand the new material also. And if, one day, we understand why the new material is better, we might be able to turn just the right knob on our deposition machine to increase the efficiency even further….

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