Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan.
ACS Nano. 2011 Feb 22;5(2):1215-22. doi: 10.1021/nn1028373. Epub 2011 Jan 4.
Short-wavelength electroluminescence (EL) emission is observed from unipolar and ambipolar carbon nanotube field-effect transistors (CNFETs) under high bias voltage. EL measurements were carried out with an unsuspended single-walled carbon nanotube (SWNT) in high vacuum to prevent the oxidation damage induced by current heating. Short-wavelength emission under high bias voltage is obtained because of the Schottky barrier reduction and the electric field increase in a SWNT. The simultaneous measurements of transport and EL spectra revealed the excitation mechanism of impact excitation or electron and hole injection dependent on the conduction type of unipolar or ambipolar characteristics. In addition to the EL emission, blackbody radiation was also observed in a p-type CNFET. Taking into account the device temperature estimated from blackbody radiation, the contribution of impact excitation and thermal effect to the exciton production rate was evaluated.
短波长电致发光 (EL) 发射可从单极和双极碳纳米管场效应晶体管 (CNFET) 在高偏压下观察到。EL 测量是在高真空下用未悬浮的单壁碳纳米管 (SWNT) 进行的，以防止电流加热引起的氧化损伤。由于肖特基势垒降低和 SWNT 中的电场增加，在高偏压下获得了短波长发射。输运和 EL 光谱的同时测量揭示了基于单极或双极特性的传导类型的冲击激发或电子和空穴注入的激发机制。除了 EL 发射之外，在 p 型 CNFET 中还观察到黑体辐射。考虑到从黑体辐射估计的器件温度，评估了冲击激发和热效应对激子产生速率的贡献。
