Photodetectors based on treated CdSe quantum-dot films

Publication Type:

Journal Article

Source:

Appl. Phys. Lett., AIP Publishing, Volume 87, Issue 21, p.213505 (2005)

ISBN:

0003-6951

Keywords:

2005, 2013 and earlier

Abstract:

We demonstrate photodetectors of sandwich geometry active in the visible spectrum in which the active layer is a 200 nm thick film of CdSequantum
dots(QDs). The solution-phase treatment of the QDfilm with n -butylamine
after casting greatly increases the exciton dissociation efficiency and
charge-transport properties of the film. Under 110 mW ∕ cm 2 illumination
with light at λ = 514 nm , the photocurrent to dark current ratio, I photo
∕ I dark , is 10 3 at V = 0 V , and the 3 dB frequency is ∼ 50 kHz . At
room temperature, we observe zero-bias external quantum efficiencies (EQE)
from 0.08% to 0.23% in the wavelength range λ = 350 nm to λ = 575 nm ,
corresponding to an internal quantum efficiency (IQE) of 0.6 ± 0.1 %
across the tested spectrum. At V = − 6 V , EQE ranges from 15% to 24%,
corresponding to an IQE of 70 ± 10 % .