#227 from R&D
Innovator Volume 5, Number 7
Answer Came in a Dream
Dr. Rauf is a
research scientist in the department of physics, Queen’s
When someone asks
me what was behind my invention of a superior thin film, I say it
must have been part of a Divine design.
I began working on thin films at Punjab University in
Pakistan. Having done
very well in my studies at Punjab University, I was awarded
several fellowships and went to Cambridge University to pursue a
Ph.D. degree, doing research on tin-doped indium oxide (ITO).
This material has properties that make it especially
useful. It reflects
in the infrared region (heat radiation), absorbs UV, transmits
visible light, and conducts electricity.
ITO is used in solar cells as well as flat-panel display
devices such as laptop computers, digital watches, and
wanted me to study the mechanism that hinders electron passage in
thin films of ITO. I surveyed the work in the field and concluded
that the tin dopant atoms, which are introduced to generate mobile
electrons, hinder electron passage through the material.
I suggested to my supervisor that the way to study this
phenomenon is to produce a multilayer stack of alternating doped
and pure indium oxide layers, so that electrons are produced in
the doped layer and will then move freely in the undoped layer.
Therefore, if the electrical properties of the proposed
multilayer structure are significantly improved, that would prove
that the dopant is the dominating factor in hindering the path of
the electrons. If
this layering experiment doesn't improve electron mobility, then
the experiment would have eliminated one factor from the list of
to Follow My Own Plan
But my supervisor
just smiled and said, "It's not that simple.
I suggest that you start depositing amorphous ITO films and
study their microstructure and other properties."
The money funding my supervisor’s position came from
industry, and it seemed that the kind of work was strictly
specified. Because of
my strong religious background, I didn't argue with him, and began
following his approach. After
a year of work, I wasn't able to achieve any significant results. Again, I requested permission to pursue my original strategy;
but my supervisor wouldn't relent.
We had an argument and he stopped supporting my work.
Fortunately, through my fellowships, I could still continue
my research. So now I
was free of the industrial connection and pursued the direction I
felt would be more important.
Repeat the Results
The first thing I
did was to design and construct a substrate heater.
This was a simple apparatus, with wound metal wires (like
in room heaters). A
thin mica sheet was placed over the coils, and a 4 mm thick copper
plate was put over the mica sheet to produce a uniform temperature
on the substrate surface. This
was important as a small variation in temperature may generate
stresses in the films, and therefore adversely affect the film's
prepared by making a high-temperature vapor of ITO and allowing
the vapor to deposit on a glass slide resting on the heated copper
plate. After each
experiment, I had to take the heating apparatus apart for
One day, I
prepared a film that had electrical conductance four times greater
than I had previously observed!
I couldn't believe these results, so I repeated the
experiment, and was extra careful.
Unfortunately, I just couldn't make another film having
that superior quality. What
was going on?
I showed the
"superior" sample to my supervisor who was very
impressed and sent it to Pilkington Brothers Ltd., the largest
European marketer of coated glass.
They were also impressed and one of their physicists asked
me how that particular sample was made.
I responded, "I don't know."
But my supervisor smiled, and said, "We'll try and
reproduce the results." I visited Pilkington Brothers and talked about my work.
Soon I received a generous check from them with a note
stating that I had no obligations associated with accepting the
money. This was good
timing, as I was in need of funds then to pay various university
supervisor began to put enormous pressure on me to tell him what I
did that yielded those special samples.
As hard as I tried, I just couldn't figure out what I did
different that day. He
became very angry and threatened that I would not get my Ph.D.
unless I told him. I
felt that I had to report this to he department head who then
tried to reconcile us.
I examined the
microstructure of the superior film and showed that it was quite
different, but we just couldn't understand how that structure was
formed. Soon after,
however, my supervisor told me that he is responsible for knowing
what I do, and if the situation doesn't change that he might lose
his job. He then
threatened to prevent me from writing my theses unless I tell him
how I made that film. This
put even greater pressure on me.
I could stand it no longer, so I spoke to the head of the
microstructure research group.
He seemed to understand my predicament and gave me
permission to write a thesis under his guidance.
Answer Came in a Dream
About two weeks
later I had a dream. I
saw myself getting ready to prepare a thin-film sample and, while
putting the heater together, I picked up the copper plate and said
to myself, "I don't need this, I'll put the substrate in
direct contact with the heater coils."
Then, in the dream, I start evaporating the material, and
saw the heater coils turn into red-hot brooms, sweeping back and
forth. I saw them
drag the dopant atoms into certain regions.
The dream had a dramatic impact on me, so the next day I
set up an experiment without the copper plate.
And guess what? The
resulting film had those superior properties!
Now I figured out what I had done in that first
My mind must have been on something else the day I did that
“successful” experiment, as I must have forgotten to put the
copper plate on the heater. The ITO was deposited on the glass slide having strips of
warm and hot temperatures resulting from the closeness of each
It seems that the
temperature gradients, in the absence of the copper plate, sweep
the defects to the warmest side of each deposited ITO grain.
Because defects migrate the same way in neighboring grains,
the lattices also become similarly aligned, and this property then
dramatically increases conductance of the thin film.
After my Ph.D., I
went to Queen’s University as a postdoctoral fellow to work on
steels, a project having nothing to do with thin films. My supervisor, however, graciously allowed me to pursue
thin-film research in my spare time.
I developed better ways to engineer ITO grain orientation
as well as to enhance crystal lattice alignment.
This work was going so well that I took a research
scientist position with professor Michael Sayer, at Queen’s, to
work full time on thin films.
We are developing a laboratory process into an industrially
feasible technique for high-quality think-film deposition.
A few months ago,
I presented my findings at the Material Research Society meeting
in Boston, and was very pleased at all the attention my work
gained. I continue to
wonder how that dream came about.
Perhaps a Divine reward for my strong belief in Islam?