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Jeudi 30 Janvier 2014, 14h
Amphi Holweck, Esc C, 1ème etage
How to make film of colloidal quantum dots conductive
Emmanuel Lhuillier
LPEM
My talk will start with some general considerations about colloidal
semiconductor quantum dots. I will in particular highlight how this
system, which is obtained from a chemichal synthesis, has reached a high level of maturity and can compete with epitaxially grown heterostructure. Then I will focus on the transport properties of QD and I will show that two parameters drive the level of conduction which are the interparticle mobility and carrier density. In my talk I will in particular interest toHgTe quantum dots and CdSe colloidal quantum wells.
In a second part I will discuss how it is possible to tune the
interparticle coupling to reach high mobility films. And I will apply this result to the photoconduction properties of mid infrared (3-5µm) HgTe QD.I will in particular show how we can improve by two decades the
detectivity of QD based mi-IR photodetector by encapsulating the QD in the right passivating matrix. If I have time I will also discuss about the noise in film of colloidal QD.
Finally I will expose recent results about the charging of colloidal QD
using solid electrolyte. Our method is applied to colloidal quantum well
and has lead to exceptional performances for electrolyte gated field
effect transistor with record on/off ratio. Carrier density as high as
1020cm-3 are achieved thanks to bulk doping of the film.