Journal of Nano Research Vol. 59

Abstract: Structural, optical and electrical properties of SnO₂ thin films deposited by spray ultrasonic technique were investigated by varying substrate temperature. The structural characterization of the films was analyzed via X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). Films surface morphologies were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optical absorption spectrum was recorded using the UV–Vis spectroscopy and the films were found to be transparent. Optical measurements showed that the layers had a relatively high absorption coefficient of 10⁵ cm⁻¹. A shift in the absorption edge was observed and the films exhibited direct transitions with band gap energies ranging from 3.85 to 3.94 eV.

Abstract: The paper proposes analytical model for Gate-All-Around Metal Oxide Semiconductor Field Effect Transistor (GAA-MOSFET) for germanium channel including quantum mechanical effects. It is achieved by solving coupled Schrodinger-Poisson’s equation using variational approach. The proposed model takes quantum confinement effects to obtain charge centroid and inversion charge model. By using these models the quantum version of inversion layer capacitance, inversion charge distribution function and Drain current expressions are modelled and the performance evaluation of the developed model is compared with Silicon channel GAA-MOSFET. Analytically modelled expressions are verified by comparing the model with simulation results.

Abstract: In this paper for the first time, the performance of Dielectric Engineered Tunnel Field Effect Transistors (DE-TFETs) is evaluated on the InGaAs channel. Two DE-TFETs based on gate-dielectric structures, namely, Device-A and Device-B are modeled and characterized for both n-type and p-type operations to attain low subthreshold slope (SS) and drain induced barrier lowering (DIBL) using La₂O₃ as high-k gate dielectric. A structural modification of Device-B is illustrated that improves the on-state current (I_on), SS, and DIBL. Then, performance of both devices are analyzed based on physical oxide thickness (T_ox). The simulation results show that the modified Device-B has the lowest SS of 15.31 mV/dec and 54.64 mV/dec, I_on/I_off ratio of ~10⁹ and ~10⁶ with off-state current (I_off) of ~10^-15 A/µm and ~10^-12 A/µm for n-DE-TFET and p-DE-TFET, respectively. Furthermore, the performance parameters of both devices are studied for digital and analog applications and it is found that the modified Device-B can be a potential candidate for future digital applications due to its low power dissipation of 13.55 µW/µm and 27.56 µW/µm for n-DE-TFET and p-DE-TFET, respectively. On the other hand, Device-A shows high transconductance (g_m) of 722.52 µS/µm and 424.3 µS/µm and cut-off frequency (f_T) of 211.95 GHz and 290.86 GHz for n-DE-TFET and p-DE-TFET, respectively, and can be a viable candidate for future low power analog applications.

Abstract: We present the rational synthesis of novel nanocrystals CuS (nc-CuS) by single source molecular precursor (SSMP) method. Among the present materials synthetic routes, the SSMP route is high efficient and comfortable way to construct nanostructured materials. Both CuS nanocrystals capped with hexadecylamine (HDA) and trioctylphosphine oxide (TOPO) have been synthesized by thermolysing bis (N-diisopropyldithiocarbamate)Cu (II) complex at 180 °C. Various physicochemical characterizations such as SEM images of nc-CuS exhibited uniform exfoliated surface morphologies with uniform continuous network of about 50 μm agglomerated particles. Our method could be broadly applicable for the preparation of other high quality yield metal sulfide nanostructures

Abstract: Graphene is one of the most promising materials discovered in last years. It is usually synthesized by Hummers’ method requiring the usage of many chemicals. As an alternative to traditional methods, in this study a bottom-up synthesis method was developed from various saccharides such as starch, mannose, cellulose, fructose, arabinose, and xylose by carbonization at 600 °C to 800 °C in LiCl/KCl molten salt system. The proposed method is environmental friendly and economic. Graphene yields at 600 °C are higher than at 800 °C. Graphene products give peak at 2θ = 23° on the X-Ray Diffraction (XRD) patterns. As the temperature is increased, amorph structure is observed on the XRD patterns. Raman spectroscopy results show that intensity of D band peak over intensity of G band peak (ID/IG) values of graphene products synthesized from arabinose and cellulose at 600 °C, graphene from arabinose synthesized at 800 °C are 0.76, 0.65 and 0.85 respectively, which show that these products are few-layered. According to X-ray photoelectron spectroscopy (XPS) results, graphene products synthesized at 600 °C have higher carbon content than those synthesized at 800 °C.