Transcript A sample file is available here.

OFET devices for Zhiqiang/Basov IR experiment (03.21.2007)
ITO(24nm)/parylene(<d> = 1.14m)/rubrene OFETs, made 03.21.2007
device #1
device #2
device #3
device #4
Please, look at the top surface of each device under an optical zoom-microscope in reflection. This will help to identify the most flat
regions within each channel. Most of the devices have some large flat areas in the channel, but they also have some steps or unevenness;
it should be ok, however, if the position of the excitation spot is fixed with respect to the crystal during an individual measurement as a
function of frequency or T. Device #4 has a huge channel (~ 7 mm dia): it might be useful if you want to defocus the beam and collect the
signal from a large area. Remember to avoid gating the devices when they are under illumination with a light of wavelength < 560 nm (for
the same reason as before: photo-induced charge transfer under an applied VG which results in a shift of the threshold voltage). See the
device layout and OFET electrical measurements for each device on next slides.
Device layout
This is a silver patch coated with
parylene; it is only for the purpose
of a better fixation of the crystal to
the substrate. Not for contacting!
24 nm ITO gate.
20-m gold wires (Source,
Drain and Gate); they are
bare wires, so you do not
need to strip parylene off
them.
Gate
Hard plastic substrate
15mmx15mm and 1 mm
thick with an orifice.
Exposed silver pads
corresponding to the Gate, Source
and Drain (not coated with
parylene); can be used for
contacting.
Source
Drain
50-m gold wires (Source and
Drain); they are extending from
the graphite electrodes to the
silver pads on the substrate.
Since the crystal is not glued to
the substrate, these thicker and
relatively stiffer wires help to
hold the crystal sturdy. The
Drain wire runs across the
crystal, and it is attached to the
substrate by two silver pads
and to the crystal by the
graphite contact. Besides being
the Drain contact, it serves as a
“clamp” that holds the crystal
down to the substrate.
Transconductance measurements of these OFETs: no leaks or other problems found
ITO(24nm)/parylene(mm)/rubrene OFETs, 03.21.07
-6
OFET 1, W/L~0.5
OFET 2, W/L~1
OFET 3, W/L~0.5
OFET 4, W/L~1
2.5x10
-6
ISD (A)
2.0x10
-6
1.5x10
All VSD = 5V
-6
1.0x10
-7
5.0x10
0.0
-70
-60
-50
-40
-30
-20
VG (V)
-10
0
10
C:/ourdata/rb/032107/...
20