<s>
Molecular-beam	B-Algorithm
epitaxy	I-Algorithm
(	O
MBE	O
)	O
is	O
an	O
epitaxy	O
method	O
for	O
thin-film	O
deposition	O
of	O
single	O
crystals	O
.	O
</s>
<s>
MBE	O
is	O
widely	O
used	O
in	O
the	O
manufacture	O
of	O
semiconductor	O
devices	O
,	O
including	O
transistors	B-Application
,	O
and	O
it	O
is	O
considered	O
one	O
of	O
the	O
fundamental	O
tools	O
for	O
the	O
development	O
of	O
nanotechnologies	O
.	O
</s>
<s>
MBE	O
is	O
used	O
to	O
fabricate	B-Architecture
diodes	O
and	O
MOSFETs	B-Architecture
(	O
MOS	O
field-effect	O
transistors	B-Application
)	O
at	O
microwave	O
frequencies	O
,	O
and	O
to	O
manufacture	O
the	O
lasers	O
used	O
to	O
read	O
optical	B-Device
discs	I-Device
(	O
such	O
as	O
CDs	B-Device
and	O
DVDs	O
)	O
.	O
</s>
<s>
Molecular-beam	B-Algorithm
epitaxy	I-Algorithm
takes	O
place	O
in	O
high	O
vacuum	O
or	O
ultra-high	O
vacuum	O
(	O
10−8	O
–	O
10−12Torr	O
)	O
.	O
</s>
<s>
The	O
gaseous	O
elements	O
then	O
condense	B-Algorithm
on	O
the	O
wafer	O
,	O
where	O
they	O
may	O
react	O
with	O
each	O
other	O
.	O
</s>
<s>
When	O
evaporation	B-Algorithm
sources	O
such	O
as	O
copper	O
or	O
gold	O
are	O
used	O
,	O
the	O
gaseous	O
elements	O
impinging	O
on	O
the	O
surface	O
may	O
be	O
adsorbed	O
(	O
after	O
a	O
time	O
window	O
where	O
the	O
impinging	O
atoms	O
will	O
hop	O
around	O
the	O
surface	O
)	O
or	O
reflected	O
.	O
</s>
<s>
The	O
term	O
"	O
beam	O
"	O
means	O
that	O
evaporated	O
atoms	O
do	O
not	O
interact	O
with	O
each	O
other	O
or	O
vacuum-chamber	O
gases	O
until	O
they	O
reach	O
the	O
wafer	O
,	O
due	O
to	O
the	O
long	O
mean	B-Algorithm
free	I-Algorithm
paths	I-Algorithm
of	O
the	O
atoms	O
.	O
</s>
<s>
Molecular-beam	B-Algorithm
epitaxy	I-Algorithm
(	O
MBE	O
)	O
is	O
also	O
used	O
for	O
the	O
deposition	O
of	O
some	O
types	O
of	O
organic	B-Algorithm
semiconductors	I-Algorithm
.	O
</s>
<s>
Other	O
variations	O
include	O
gas-source	B-Algorithm
MBE	I-Algorithm
,	O
which	O
resembles	O
chemical	B-Algorithm
vapor	I-Algorithm
deposition	I-Algorithm
.	O
</s>
<s>
One	O
of	O
the	O
most	O
accomplished	O
achievements	O
of	O
molecular-beam	B-Algorithm
epitaxy	I-Algorithm
is	O
the	O
nano-structures	O
that	O
permitted	O
the	O
formation	O
of	O
atomically	O
flat	O
and	O
abrupt	O
hetero-interfaces	O
.	O
</s>
<s>
Most	O
recently	O
the	O
construction	O
of	O
nanowires	B-Architecture
and	O
quantum	O
structures	O
built	O
within	O
them	O
that	O
allow	O
information	O
processing	O
and	O
the	O
possible	O
integration	O
with	O
on-chip	O
applications	O
for	O
quantum	O
communication	O
and	O
computing	O
.	O
</s>
<s>
These	O
heterostructure	O
nanowire	B-Algorithm
lasers	I-Algorithm
are	O
only	O
possible	O
to	O
build	O
using	O
advance	O
MBE	O
techniques	O
,	O
allowing	O
monolithical	O
integration	O
on	O
silicon	O
and	O
picosecond	O
signal	O
processing	O
.	O
</s>
<s>
The	O
Asaro	O
–	O
Tiller	O
–	O
Grinfeld	O
(	O
ATG	O
)	O
instability	O
,	O
also	O
known	O
as	O
the	O
Grinfeld	O
instability	O
,	O
is	O
an	O
elastic	O
instability	O
often	O
encountered	O
during	O
molecular-beam	B-Algorithm
epitaxy	I-Algorithm
.	O
</s>
