Temperature-, gate-, and photoinduced conductance of close-packedCdTenanocrystal films

Measuring charge trap occupation and energy level in CdSe/ZnS quantum dots using a scanning tunneling microscope

“…30 The samples are annealed at 120°C for 1 h in low vacuum conditions ͑8 Torr͒ in a Centurion Qex furnace ͑DENTSPLY Ceramco͒ to evaporate some of the capping ligands from the surface of the QDs. 6,31 Atomic force microscopy ͑AFM͒ images, shown in Fig. 2 ͑obtained on a DI Dimension 3000 in tapping mode͒ of as-deposited and annealed QD submonolayers showed a reduction in the distance between the top of the QD and the Au surface for the annealed QDs of 0.6 nm, suggesting that some of the ligands left the QDs.…”

Interfacial Recombination for Fast Operation of a Planar Organic/QD Infrared Photodetector

“…Specifi cally, we incorporate a fi lm of the fullerene derivative, [6,6]-phenyl C61-butyric acid methyl ester (PCBM), which creates a type-II hetero-interface with PbS QDs, into a planar PbS QD photoconductor structure. Charge separation at a QD/fullerene interface was fi rst reported by Biebersdorf et al [ 27 ] and later exploited to realize a planar photodetector structure consisting of a blend of as-synthesized PbS QDs (insulated with long oleic acid ligands) with PCBM.…”

Charge transport in mixed CdSe and CdTe colloidal nanocrystal films

“…CdTe and CdSe NCs were synthesized using standard methods for II-VI NC synthesis 15,16 and CdSe/CdTe rod/dot NBs ͑CdSe/CdTe NBs͒ were synthesized using a previously published procedure. 17,18 The CdTe NCs were 6 nm in diameter and the CdSe NCs were 4.9 nm in diameter.…”

“…Temperaturedependence measurements of the dark current in NB films yields an activation energy of 0.33 eV for the dark current, nearly identical to that of CdTe NC films. 15,18 Figure 4 shows the dark conductivity and photoconductivity of a CdTe NC film as a function of field and air expo-sure. An increase in both the dark current and photocurrent is observed with increasing exposure time to air under ambient conditions while the insets in Figs.…”