Crystal Growth - Formation and Growth of Germaniumsulfide Crystals by the Sublimation Method; Variation of the Pulling Rate
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| License | No Open Access License: German copyright law applies. This film may be used for your own use but it may not be distributed via the internet or passed on to external parties. | |
| Identifiers | 10.3203/IWF/E-2670eng (DOI) | |
| IWF Signature | E 2670 | |
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| IWF Technical Data | Film, 16 mm, LT, 99 m ; SW, 9 min |
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00:00
QuartzCell growthMortality rateGermaniumElectric arc furnaceSetzen <Verfahrenstechnik>Tube (container)Lot <Werkstoff>Human body temperatureInitiation (chemistry)Sulfide
01:11
Mortality rateQuartzCell growthKorngrenzeCrystal
01:46
Cell growthLot <Werkstoff>Mortality rateKorngrenzeSetzen <Verfahrenstechnik>QuartzSurface scienceSeafloor spreading
03:26
Reaction mechanismCell growthQuartzFreezingKorngrenze
04:45
Cell growthGene duplicationAssetWasserwelle <Haarbehandlung>Process (computing)
05:37
Cell growthFreezingProcess (computing)QuartzZellmigration
06:40
Mortality rateGene duplicationCell growth
07:21
Separation processKorngrenzeQuartzCell growthMortality rateSoil compaction
Transcript: English(auto-generated)
00:05
Crystal growth, formation and growth of germanium monosulfide crystals by the sublimation method. Variation of the pulling rate, an ampoule is slowly pulled up through a
00:26
vertical tube furnace with a quartz window. The germanium monosulfide is placed at the bottom of the ampoule. Since the temperature in the upper part of the furnace is lower than at the bottom, the germanium sulfide
00:41
sublimates into the tip. The initial formation of crystals and the following growth is observed with a camera. Pulling rate 1 millimeter per day, frame
01:06
size 26 millimeters, 30 frames per hour. Just below the tip of the ampoule several crystals are formed. Their growth speed is higher than the pulling rate of the ampoule of 1 millimeter per day. Finally the
01:30
crystal forms a convex interface. Pulling rate 3 millimeters per day, 120, 40, 72
01:43
frames per hour. In this run too the seeds are formed below the tip. The tip is only filled up now. The interface remains nearly convex and the growth
02:02
speed is nearly equal to the pulling rate. This time the crystallization begins in the tip. The crystal grows in the vertical direction with an almost
02:27
flat interface. The horizontal growth seems to be partially split. A single
02:47
seed is formed in the tip and spreads at high speed along the ampoule wall. Its surface is irregular because of secondary seed formation. The
03:12
horizontal growth seems to be once more partially split because of the formation of needles. Pulling rate 10 millimeters per day, 30, 120, 10 frames
03:32
per hour. Again the seed is formed below the tip. The shape of the
03:45
interface becomes quickly convex and there is a higher reflecting facet to be seen at the right. The crystal facet below right about one day later. The
04:11
growth continues by spreading growth layers over the facet from above. We
04:20
repeat the scene and show after a freeze frame the underside of the crystal facet in magnification. After tracking in to close up the experiment begins. The growth mechanism for the crystal facet on the right can be observed in more detail in contrast to the normal interface below. Another
04:46
repetition. The growth is continued. The wave-like incorporation process on the growth asset can be observed clearly. In this magnification the film has been
05:08
additionally slowed down three times by frame duplication. The growth layers spread like liquid waves although they consist of solid material. Two
05:40
crystals grow down along the ampoule wall at a relatively high speed. The
05:51
space between the crystals is only filled up slowly. A seed is formed in
06:10
the tip, migrates down a little before growth is resumed relatively rapidly. Once more repetition and magnification show the process in
06:23
greater detail. After a freeze frame and close-up the experiment starts. The once more a repetition of the phenomenon shown three times slower by
06:44
frame duplication. Start of the experiment. The seed migrates down out of the tip, remains stationary for a short time before it continues to
07:03
migrate and grow. Spontaneous growth. Pulling rate 30 millimeters per day, one frame per minute. At this relatively high pulling rate the shape of the
07:29
interface changes from flat to concave and degenerates into needles. Pulling
07:45
rate 100 millimeters per day, six frames per minute. Far from the ampoule tip several seeds are formed. They spread needle-like in several directions without correlation to the temperature field. At this high pulling rate of 100
08:09
millimeters per day, growth of compact crystals is no longer possible.