Experimental corrections for the hot hole distribution function in germanium in crossed electric and magnetic fields

A procedure for finding corrections for the hot hole distribution functions obtained from absorption measurements on intersubband transitions of hot heavy and light holes in germanium in crossed electric and magnetic fields is proposed. This procedure is based on the multiple-valued dependence of the absorption on the photon energies of transitions from light holes to a subband split off as a result of the spin-orbit interaction. Taking these corrections into account improves the agreement between the gain for direct optical transitions between the light and heavy hole subbands calculated from measurements of the absorption in the near-infrared and direct measurements in the far-infrared. Fiz. Tekh. Poluprovodn. 32, 1197–1199 (October 1998)     

Amplification of radiation in the far infrared range by hot holes in germanium in crossed electric and magnetic fields

The results of direct gain measurements are reported for the amplification of polarized and unpolarized, long-wavelength, infrared radiation by hot holes in germanium in crossed electric and magnetic fields in the Voigt and Faraday configurations. The experimental data are compared with gain calculations. Fiz. Tekh. Poluprovodn. 31, 1482–1486 (December 1997)     

Physics of Gate Modulated Resonant Tunneling (RT)-FETs: Multi-barrier MOSFET for steep slope and high on-current

A new concept of nanoscale MOSFET, the Gate Modulated Resonant Tunneling Transistor (RT-FET), is presented and modeled using 3D Non-Equilibrium Green’s Function simulations enlightening the main physical mechanisms. Owing to the additional tunnel barriers and the related longitudinal confinement present in the device, the density of state is reduced in its off-state, while remaining comparable in its on-state, to that of a MOS transistor without barriers. The RT-FET thus features both a lower RT-limited off-current and a faster increase of the current with V_G, i.e. an improved slope characteristic, and hence an improved I_on/I_off ratio. Such improvement of the slope can happen in subthreshold regime, and therefore lead to subthreshold slope below the kT/q limit. In addition, faster increase of current and improved slope occur above threshold and lead to high thermionic on-current and significant I_on/I_off ratio improvement, even with threshold voltage below 0.2 V and supply voltage V_dd of a few hundreds of mV as critically needed for future technology nodes. Finally RT-FETs are intrinsically immune to source-drain tunneling and are therefore promising candidate for extending the roadmap below 10 nm.     

一种局域化协同增强太赫兹波电磁场的超材料

设计了一种太赫兹(THz)波段的超材料,可以实现 对垂直入射THz波的电、磁场局域化协同增强。数 值仿真表明,在线偏振的THz脉冲垂直辐照下,利用本文超材料的结构能得到强显著增强且 高度局域化的电、磁场 分布,入射THz波的电、磁场分量可以分别增强20倍;被增强的电、磁场局域化 在μm²尺度范 围内,且在空间上不重叠。基于等离激元理论分析了超材料内部的面电流分布以及超材料内 部电 荷的积累,给出了电磁场协同增强及局域化的理论解释,即超材料的特殊结构产生的 电容效应及面 电流的汇聚作用分别是导致电、磁场协同局域化增强的原因。最后,具体分析了超材料关键 的几何参数对 于场增强效果的影响。本文提出的超材料方案,有望应用于THz波段近场光学、非线性光 学及THz波与磁有序介质相互作用等领域。