Partha Sharathi Mallick

The scattering angle between electrons plays a very important role for the calculation of scattering probability. The probability of scattering is an essential parameter for the simulation of electron paths. In this work, we calculated the scattering probability with scattering angle in AlGaN and InGaN at 77 K and found that the lower angle scatterings only dominate.

In order to construct a dense Photonic Integrated Circuit (PIC) that comprises photonic waveguides, it is vital to consider the necessity of low crosstalk between surrounding waveguides. From past literature, higher coupling length can be obtained by utilizing a silicon – on -insulator (SOI) based photonic waveguide with an acceptable waveguide separation between them. The current research aims to reduce waveguide separation and hence increase photonic integration over PICs. Numerous strips were inserted between the photonic waveguides to achieve this. The impact of modifications in height and width of three, four, and five strips on coupling has been analyzed. This has led to the inference that larger coupling lengths can be achieved. The greatest coupling lengths of 485 µm, 620 µm, and 104110 µm were reached with end-to-end waveguide separations between the two adjacent waveguides of 175 nm for three strips, four strips and five strips inserted between two photonic waveguides. Achieving a coupling length of 104110 µm proves that the proposed design is better than previously proposed designs in terms of coupling length. In addition, we have compared the coupling lengths obtained when Ge strips and Si strips were inserted between the photonic waveguides. The method given in this paper can be used to design a variety of photonic applications.

This paper proposes novel triangular cross-sectioned geometry of carbon nanotube (CNT) bundles for crosstalk and delay reduction in CNT bundle interconnects for VLSI circuits. First, we formulate the equivalent single conductor (ESC) transmission line models of the interconnects. Through SPICE analysis of the ESC circuits, we find the propagation delays of the proposed CNT bundles. Next, we model the capacitively coupled interconnects for crosstalk analysis. It is found that the coupling capacitance of triangular CNT bundle is 29% lesser than the traditionally used square CNT bundles. Further, the crosstalk-induced delay of triangular interconnects is found to be 30% lesser when compared to square bundle interconnects. The reduction in delay is found to increase as the number of CNTs in the bundle increases. So, we suggest that triangular CNT bundles are the most suitable candidates as global interconnects.

Sub‐threshold voltage operated circuits are the future for ultra‐low‐power applications. These circuits are inherently slow due to the very small sub‐threshold currents. Here, the authors propose two approaches for improving the speed of SWCNT bundle interconnects driven by CNTFET‐based circuits under sub‐threshold conditions. First, the authors modulate the channel length of the CNTFETs that are used in the driver circuits to increase sub‐threshold output current. The output current is maximum when the channel length is optimised to 15 nm. Second, the authors design driver circuits made of CNTFET‐based inverters and transmission gates for SWCNT bundle interconnects at sub‐threshold voltages. The authors consider five different configurations of the driver and load circuits. SPICE simulations show that transmission gates play a vital role in driver circuits by reducing the propagation delay and increasing the switching speed at high frequencies. Finally, the authors perform temperature‐dependent analysis of the best cases from the proposed circuits and show that the propagation delay and power dissipated by them increases drastically at increased temperatures up to 500 K.

Summary: In this paper, a high data rate bidirectional relay network is proposed by combining the merits of spatial modulation (SM) and physical layer network coding. All nodes in the network are equipped with multiple antennas. Spatial modulation technique is used to reduce hardware complexity and interchannel interference by activating only one antenna at any time during transmission. In the proposed bidirectional relay network, transmit antennas are selected at the source nodes and relay node on the basis of the order statistics of channel power. It increases received signal power and provides a significant improvement in the outage performance. Also, the data rate of the proposed network is improved by physical layer network coding at the relay node. A closed form analytical expression for the outage probability of the network over Nakagami‐m fading channel is derived and validated by Monte Carlo simulations. In addition, asymptotic analysis is investigated at high signal‐to‐noise ratio region.The outage performance of the proposed network is compared with SM and physical layer network coding bidirectional relay network without transmit antenna selection and point‐to‐point SM. With approximate SNR≈1 dB difference between the two networks, the same data rate is achieved.

Carbon nanotube (CNT) interconnects are emerging as the ultimate choice for next generation ultra large scale integrated (ULSI) circuits. Significant progress in precise growth of aligned CNTs and integration of multiwalled CNT interconnects into a test chip make them promising candidates for future nanoelectronic chips. Tremendous research efforts were made on silicon based ultra-low-k dielectrics for Cu interconnects, but, the most recent advancements in polymer based composites as dielectric materials open up fresh challenges in the use of low-k dielectrics for CNT interconnects. This paper reviews the emerging polymer composites like Boron Nitride Nanotubes, Graphene/Polyimide composites, Metal Organic Frameworks and small diameter CNTs. Many reviews are already exists on the synthesis, fabrication, dielectric, mechanical, chemical and thermal properties of these materials. In this review, we have explained the specific properties of these materials and the necessities for integrating them into CNT interconnects to meet the requirements of future IC designers.Keywords: low-k dielectric materials, ultra low-k dielectrics, carbon nanotubes, interconnects, dielectric constant,