A direct transfer method for fabricating flexible electronics without the assistance of an adhesive layer and stamp is reported in this paper. This rapid and simple method provides an approach for the application of vertically aligned carbon nanotubes (VA-CNTs) on plastic substrates. After transfer, the VA-CNTs maintained their initial orientation in the designed pattern and showed sufficient adhesion to the substrate under extreme bending conditions. The flexible device performed an emission on the transparent substrate and showed a low turn-on of 1.13 V/μm. This VA-CNT-based flexible device, which exhibits electrical resistance sensitive to bending, is also described herein.

The origin of current reduction in an infrared hot-electron transistor is examined by studying the thermal activation energy of the emitter and the collector dark current as a function of emitter bias Ve. For the emitter, the activation energy Eae is found to be determined by the thermionic emission (TE) process at a small Ve. At higher Ve, Eae decreases linearly with Ve due to the increase of the thermally assisted tunneling (TAT) current enhanced by dopant migration. For the collector, the activation energy Eac is significantly higher than Eae at low biases, indicating that the collector accepts higher energy electrons injected from the emitter. For the device under study, at Ve=0.5 V, the value of Eac is the same as that of the emitter at low biases. This result shows that, up to this bias, the collector dark current consists of only the TE current but not the TAT current, thus greatly improving the detector performance.