Electrical properties of evaporated CdSe films

Sharma, Kriti; Barua, K.

doi:10.1088/0022-3727/12/10/015

Cited by 23 publications

(9 citation statements)

References 11 publications

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“…As already demonstrated, in this low voltage regime the back-to-back Schottky model (eq ) predicts the current as a function of E app . Slopes larger than 2.0 are observed for all devices at E app > 5 V. As previously described, − slopes exceeding 2.0 signal that the SCLC current is augmented by other transport mechanisms such as P–F emission or Schottky emission.…”

Section: Resultssupporting

confidence: 74%

Electrodeposited, Transverse Nanowire Electroluminescent Junctions

Qiao

Dutta

et al. 2016

ACS Nano

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The preparation by electrodeposition of transverse nanowire electroluminescent junctions (tn-ELJs) is described, and the electroluminescence (EL) properties of these devices are characterized. The lithographically patterned nanowire electrodeposition process is first used to prepare long (millimeters), linear, nanocrystalline CdSe nanowires on glass. The thickness of these nanowires along the emission axis is 60 nm, and the width, wCdSe, along the electrical axis is adjustable from 100 to 450 nm. Ten pairs of nickel-gold electrical contacts are then positioned along the axis of this nanowire using lithographically directed electrodeposition. The resulting linear array of nickel-CdSe-gold junctions produces EL with an external quantum efficiency, EQE, and threshold voltage, Vth, that depend sensitively on wCdSe. EQE increases with increasing electric field and also with increasing wCdSe, and Vth also increases with wCdSe and, therefore, the electrical resistance of the tn-ELJs. Vth down to 1.8(±0.2) V (for wCdSe ≈ 100 nm) and EQE of 5.5(±0.5) × 10(-5) (for wCdSe ≈ 450 nm) are obtained. tn-ELJs produce a broad EL emission envelope, spanning the wavelength range from 600 to 960 nm.

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Section: Resultssupporting

confidence: 74%

Electrodeposited, Transverse Nanowire Electroluminescent Junctions

Qiao

Dutta

et al. 2016

ACS Nano

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“…Current versus voltage (| I |− V ) curves were approximately symmetrical about E app = 0 V for all three of the devices explored in this study (Figure a). The pronounced curvature of these | I |− V curves is a characteristic of M–S–M devices that incorporate Schottky barriers at both contacts, − including those prepared from polycrystalline CdSe films, − and has also been reported for M–S–M structures that incorporate semiconducting nanowires. , The ohmic resistance, R , of the nc -CdSe nanowires in these two devices cannot be accurately measured from these I–V curves, but a minimum value for R can be obtained from d V /d I evaluated at high E app values . Using this estimate, the electrical resistance of the nc -CdSe nanowires annealed at 300 °C for 4 h is ∼20–30 times higher than those annealed at 450 °C for 1 h. The lower resistance of the nc -CdSe nanowires prepared at 450 °C could be a manifestation of the larger grain diameter in the nc -CdSe (Figure b) or a higher dopant density in these samples, and the relative weighting of these two contributions cannot be determined from our data.…”

Section: Resultsmentioning

confidence: 90%

Electroluminescent, Polycrystalline Cadmium Selenide Nanowire Arrays

et al. 2013

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Electroluminescence (EL) from nanocrystalline CdSe (nc-CdSe) nanowire arrays is reported. The n-type, nc-CdSe nanowires, 400-450 nm in width and 60 nm in thickness, were synthesized using lithographically patterned nanowire electrodeposition, and metal-semiconductor-metal (M-S-M) devices were prepared by the evaporation of two gold contacts spaced by either 0.6 or 5 μm. These M-S-M devices showed symmetrical current voltage curves characterized by currents that increased exponentially with applied voltage bias. As the applied biased was increased, an increasing number of nanowires within the array "turned on", culminating in EL emission from 30 to 50% of these nanowires at applied voltages of 25-30 V. The spectrum of the emitted light was broad and centered at 770 nm, close to the 1.74 eV (712 nm) band gap of CdSe. EL light emission occurred with an external quantum efficiency of 4 × 10(-6) for devices with a 0.60 μm gap between the gold contacts and 0.5 × 10(-6) for a 5 μm gap-values similar to those reported for M-S-M devices constructed from single-crystalline CdSe nanowires. Kelvin probe force microscopy of 5 μm nc-CdSe nanowire arrays showed pronounced electric fields at the gold electrical contacts, coinciding with the location of strongest EL light emission in these devices. This electric field is implicated in the Poole-Frenkel minority carrier emission and recombination mechanism proposed to account for EL light emission in most of the devices that were investigated.

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“…(2) For the in situ heating experiment, the thermal evaporation temperature (ca. 550 °C) of CdSe in TEM significantly dropped in contrast to that of the conventional thermal physical vapor deposition, which needs 725 °C (8 × 10 –6 Torr) to achieve significant vapor phase of CdSe 39. The decrease in evaporation temperature for nanosized CdSe can be explained by the size effect of the nanoparticles, i.e.…”

Section: Discussionmentioning

confidence: 96%

Conformation of Inhibitor‐Free HIV‐1 Protease Derived from NMR Spectroscopy in a Weakly Oriented Solution

2014

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Flexibility of the glycine-rich flaps is known to be essential for catalytic activity of the HIV-1 protease, but their exact conformations at the different stages of the enzymatic pathway remain subject to much debate. While hundreds of crystal structures of protease-inhibitor complexes have been solved, only about a dozen inhibitor-free protease structures have been reported. These apo-structures reveal a large diversity of flap conformations, ranging from closed, to semi-open and wide-open. To evaluate the average structure in solution, we measured residual dipolar couplings (RDCs) and compared these to values calculated for crystal structures representative of the closed, semi-open and wide-open states. The RDC data clearly indicate that the inhibitor-free protease, on average, adopts a closed conformation in solution that is very similar to the inhibitor-bound state. By contrast, a highly drug-resistant protease mutant, PR20, adopts the wide-open flap conformation.

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Electrical properties of evaporated CdSe films

Cited by 23 publications

References 11 publications

Electrodeposited, Transverse Nanowire Electroluminescent Junctions

Electrodeposited, Transverse Nanowire Electroluminescent Junctions

Electroluminescent, Polycrystalline Cadmium Selenide Nanowire Arrays

Conformation of Inhibitor‐Free HIV‐1 Protease Derived from NMR Spectroscopy in a Weakly Oriented Solution

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