Optoelectronics with Carbon Nanotubes
Optoelectronics with Carbon Nanotubes Optoelectronics with Carbon Nanotubes
We also note that the onset of the forward-biased emission coincides with the current onset, while the onset of the reverse-biased emission lags behind the current onset. This is discussed in more detail for V-8 (b) inset below, and additionally in the investigation of electroluminescence width. It should be noted that we do not observe a significant influence of the split gate in the intensity characteristics of the emitted light in the reverse direction; on the negative VDS side, the intensity is almost identical for all the split-gate settings at any given VDS value. Although there is a potential drop between the top gates, the field created by the VTGS biasing does not appear to be greater than the impact excitation threshold, since there is little dependence on that parameter. In contrast, a single-tube device operated as a unipolar emitter shows a clear dependence on bottom global gate voltage (not shown), which is reasonable because the light generation depends of the degree of band bending at contacts that controls the carrier injection rate (see Figure IV-5 inset for schematics). From such split-gate effects and the differences between the forward and reverse biases, we can conclude that the CNT film device functions as a light- emitting diode. 93
(a) (b) Figure V-8. (a) EL intensity and corresponding drain-source current characteristics (inset) as a function of source-drain voltage. The associated top gates voltages VTG1/VTG2 are denoted in the inset. Positive VDS indicates the forward-bias direction. (b) Electroluminescence intensity plotted as a function of electrical power PEL=VDS·IDS. Experimental data points are represented by symbols (open symbols: forward bias, solid symbols: reverse bias), the lines represent best fits to the experimental data points. The corresponding top gate voltages VTG1/VTG2 are also indicated. (Inset) The zoom reveals the threshold behavior. After Ref. 152. 94
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- Page 73 and 74: (a) Figure III-13. (a) Spectra from
- Page 75 and 76: DOP = I║ / (I┴ + I║) = 0.77.
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- Page 87 and 88: (a) (b) Figure IV-3. Electrolumines
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- Page 123 and 124: Bibliography 1. Avouris, P.; Chen,
- Page 125 and 126: 30. Miyauchi, Y.; Maruyama, S., Ide
- Page 127 and 128: 56. Chen, Z.; Appenzeller, J.; Knoc
- Page 129 and 130: 85. Marty, L.; Adam, E.; Albert, L.
- Page 131 and 132: 112. Steiner, M.; Freitag, M.; Pere
- Page 133 and 134: 140. Grüneis, A.; Saito, R.; Samso
(a)<br />
(b)<br />
Figure V-8. (a) EL intensity and corresponding drain-source current characteristics<br />
(inset) as a function of source-drain voltage. The associated top gates voltages<br />
VTG1/VTG2 are denoted in the inset. Positive VDS indicates the forward-bias direction.<br />
(b) Electroluminescence intensity plotted as a function of electrical power<br />
PEL=VDS·IDS. Experimental data points are represented by symbols (open symbols:<br />
forward bias, solid symbols: reverse bias), the lines represent best fits to the<br />
experimental data points. The corresponding top gate voltages VTG1/VTG2 are also<br />
indicated. (Inset) The zoom reveals the threshold behavior. After Ref. 152.<br />
94
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