THz operation of self-switching nano-diodes and nano-transistors

Abstract

By means of the microscopic transport description supplied by a semiclassical 2D Monte Carlo simulator, we provide an in depth explanation of the operation (based on electrostatic effects) of the nanoscale unipolar rectifying diode, so called self-switching diode (SSD), recently proposed in [A. M. Song, M. Missous, P. Omling, A. R. Peaker, L. Samuelson, and W. Seifert, Appl. Phys. Lett. 83, 1881Lett. 83, (2003]. This device provides a rectifying behavior without the use of any doping junction or barrier structure (like in p-n or Schottky barrier diodes) and can be fabricated with a simple single-step lithographic process. The simple downscaling of this device and the use of materials providing high electron velocity (like high In content InGaAs channels) allows to envisage the fabrication of structures working in the THz range. With a slight modification of the geometry of the SSD, a lateral gate contact can be added, so that a nanometer self-switching transistor (SST) can be easily fabricated. We analyze the high frequency performance of the diodes and transistors and provide design considerations for the optimization of the downscaling process.

THz operation of asymmetric-nanochannel devices

“…Frequencies up to at least 2.5 THz have been detected at temperatures below 150 K. However, operation at higher temperatures, as envisaged by simulations [14,15], has not been excluded, since the signal-to-noise ratio of the measurement set-up can be greatly enhanced. In particular, the use of a lock-in amplifier, rather than digital sampling through an oscilloscope, would dramatically improve the ultimate signal-to-noise ratio.…”

“…The device, being both planar and requiring only a single lithographic step, is to our knowledge the simplest diode to date. Recently, Monte Carlo simulations predicted that the device could operate at frequencies up to a few THz (wavelength ∼ 100 μm) [14][15][16].…”

“…The simple treatment developed in [17] predicted for an SSD with a channel completely depleted by surface states a current proportional to the square of the applied voltage in forward bias over threshold, or zero otherwise, in very good agreement with the experiments. A more accurate description of the transport properties of SSDs, aided by Monte Carlo simulations, in both the AC and DC regimes, is in [14][15][16]18]. …”

Enhanced terahertz detection by localized surface plasma oscillations in a nanoscale unipolar diode

“…16 Hence, some theoretical treatments are made to enhance the efficiency of the EMC simulations, which are similar to the methodology previously adopted on SSDs. 16,18 Firstly, a 2D EMC simulation is performed only on the active In 0.53 Ga 0.47 As layer, since it is the 2DEG that largely determines the electronic properties of the device. Secondly, to account for the fixed positive charges of the whole layer structure, a virtual net background doping N V = 1.0ϫ 10 17 cm −3 ͑without impurity scattering͒ is assigned to the In 0.53 Ga 0.47 As layer.…”

Electron transport in self-switching nano-diodes

“…More recently, the high frequency performance of SSD has been investigated theoretically [2,3] and experimentally [4], respectively. Both of them corroborate the possibility of SSD operating in Terahertz regime at room temperature.…”