The external performance of quantum optoelectronic devices is governed by the spatial profiles of electrons and potentials within the active regions of these devices. For example, in quantum cascade lasers (QCLs), the electric field domain (EFD) hypothesis posits that the potential distribution might be simultaneously spatially nonuniform and temporally unstable. Unfortunately, there exists no prior means of probing the inner potential profile directly. Here we report the nanoscale measured electric potential distribution inside operating QCLs by using scanning voltage microscopy at a cryogenic temperature. We prove that, per the EFD hypothesis, the multi-quantum-well active region is indeed divided into multiple sections having distinctly different electric fields. The electric field across these serially-stacked quantum cascade modules does not continuously increase in proportion to gradual increases in the applied device bias, but rather hops between discrete values that are related to tunneling resonances. We also report the evolution of EFDs, finding that an incremental change in device bias leads to a hopping-style shift in the EFD boundary – the higher electric field domain expands at least one module each step at the expense of the lower field domain within the active region.

In this article, we present dielectric modulation-based label free detection of biomolecules at a cavity under gate metal located near the tunneling junction of charge plasma based dual metal-double gate tunnel FET (CP-DM DGTFET). The biomolecules that settle down in the cavity act as dielectric above the tunneling junction and cause drain current to increase/ decrease. To eliminate the short channel impact and to enhance I _ON /I _OFF ratio without compromising any other device features, dual metal gate architecture with laterally split dielectric is used. The biosensor is capable of recognizing neutral, positive, and negative charges with the highest drain current sensitivity of 2.9×10 ⁹ Ccm ^-2 and highest I _ON /I _OFF ratio of 9.02×10 ¹¹ for biomolecule gelatin with dielectric constant k = 12. This work explores the effectiveness of charge-plasma based DM DGTFET for detection of biomolecules such as gelatin (k = 12), keratin (k = 8), bacteriophage T7 (k = 6.3), and APTES (k = 3.57) with varied charge distribution at various biasing. The drain current sensitivity, subthreshold slope, drain current, ON/OFF current ratio are computed for various biomolecules and their variations with respect to cavity length, biomolecule charge, etc. are used to detect unknown biomolecules. Finally, RF analysis such as gain bandwidth product, cut-off frequency, transit time, and linearity/selectivity of biosensors are incorporated. The device shows better linearity and less distortion for high –k biomolecules.

The incubation of strained nano-system in the form of tri-layered structure as nanowire channel in the cylindrical-gate-all-around (CGAA) FET at 10 nm gate length is developed for the first time to keep abreast with the proposed 3 nm technology node of IRDS 2022. The system installs Type-II hetero-strain alignment in the channel attesting itself as the fastest operating device debasing the SCEs at nano regime. The ultra-thin strained-channel comprises of two cylindrical s-Si wells encompassing s-SiGe barrier in between, which enables improvement of carrier mobility by succumbing of quantum charge carriers in the region. This results in 2D charge centroid creation with cylindrical based circular Nano-system contemplating electrostatic potential difference leading to enriched electric field, current density and transconductance, while the gate-all-around architecture with increased gate controllability lowers leakage current, in the device. The 10 nm strained-channel CGAA astounded havoc ON current enhancements of ~ 20% over 22 nm strained CGAA, 57% over Si CGAA FET and 75% over proposed 3 nm technology node IRDS 2022 are accomplished. Hence, carrier mobility and velocity enriches instituting quasi-ballistic transport through the Nanowire channel, thereby augments in ~ 28% drain current so the 10 nm channel CGAA FET stands as the most suitable and improved device in nano regime.