nan Rashmi

Negative Differential Transconductance and Nonreciprocal Effects in a Y-Branch Nanojunction: High-Frequency Analysis

We report on negative differential transconductance (NDT) effect in Y-branch nanojunctions which leads to small-signal nonreciprocity of the device for certain biasing schemes. We present the dc analysis of the device from which we identify the bias regions where NDT effect occurs. We compare experimental dc measurements with results of Monte Carlo simulations, which yields very good qualitative and quantitative agreement. We perform a high-frequency analysis of the NDT effect up to 110 GHz which shows that the effect discussed is still present at such high frequencies

Theoretical and experimental characterization of Y-branch nanojunction rectifier up to 94 GHz

A double Y-branch ballistic junction is proposed for rectification of signals up to 94 GHz. A nonlinear model is developed to predict the frequency dependence of its RF to DC conversion performances, and agrees very well with experiment. The model shows the importance of minimizing extrinsic parasitics when designing HF ballistic nanodevices.

Solutions for input impedance matching of nanodevices: Application to Y-Branch Junction HF to DC rectifier

The problem of high input impedance of nanoscaled devices is analyzed for the case of a Y-Branch Junction. An electrical nonlinear model of YBJs validated on measured data is used to show influence of source impedance on HF to DC detection performance in YBJ. An impedance matching network is proposed and is proven to increase the detection sensitivity. Multiple 2DEG channels material used to fabricate parallel YBJs stacked on one another is also proposed as an alternative solution to mismatch problem. It is shown that using multiple 2DEG the input impedance and reflection coefficient can be decreased but at the price of decrease in sensitivity

Analysis of Bandwidth and Nonlinear Effects in InAlAs/InGaAs/InP Based Ballistic Nanodevices for Applications up to THz Range

Analysis of nonlinear effects in InAlAs/InGaAs-based channels and three-terminal ballistic junctions (TBJs) is performed for applications up to THz range. Results show that InGaAs-based channels designed for ballistic operation exhibit high intrinsic cut-off frequency (fT ~ 10 THz). Nonlinear effects in TBJs, which result from device geometry and space charge distribution, show good qualitative agreement with published results.