The quasiparticle band structures and optical properties of ACdTS kesterite are investigated here on the basis of first-principles calculations, including the many-body effects theory, by using the GW plus Bethe-Salpeter equation. There were significant GW-quasiparticle corrections, over 0.9 eV, to the GGA-Kohn-Sham band gap. Our calculations also show that ACdTS kesterite had a small binding energy, exhibited optical absorption in the visible region, high minority carrier mobility, and large diffusion in length, rendering this material a promising candidate for solar cells. Based on these findings, we designed and implemented an ACdTS absorber in a thin-film solar cell (TFSC) structure. The new kesterite solar cell has a high efficiency of 11.6% with a low deficit in the output voltage. Moreover, a strategic combination between the particle swarm optimization approach and the ACdTS TFSC decorated with periodic nanowires is proposed to obtain significantly improved photovoltaic characteristics. The optimized design identifies a new pathway for a high conversion efficiency of 14%, far surpassing that provided by the conventional TFSC kesterite.

In this work, an inverted PTB7:PC₇₀BM bulk heterojunction solar cells with the configuration of ITO/ZnO/ PTB7:PC₇₀BM / HTMs/Ag for various inorganic materials as a hole transport layer (ZnO, MoO₃, NiO, PEDOT: PSS, V₂O₅ and Cu₂O) are simulated by using the GPVDM software which is a free general-purpose tool for the simulation of opto-electronic devices. The influence of the thickness of both PTB7:PC₇₀BM and HTMs layers on the performance of the solar cell are investigated. The obtained results indicated that on regardless on the type of the inorganic material constituted the Hole Transport Material (HTM), the solar cell parameters can be improved by reducing the HTM thickness while the active layer optimum thickness is around 90 nm. The performance of the device with all inorganic materials used as HTM reaches the same levels as the PEDOT/PSS for the lower thickness (10 nm). As the thickness is increased, the electrical parameters are significantly enhanced by inserting cuprous oxide (Cu₂O) compared to the conventional PEDOT: PSS.

The quasiparticle band structures and optical properties of ACdTS kesterite are investigated here on the basis of first-principles calculations, including the many-body effects theory, by using the GW plus Bethe-Salpeter equation. There were significant GW-quasiparticle corrections, over 0.9 eV, to the GGA-Kohn-Sham band gap. Our calculations also show that ACdTS kesterite had a small binding energy, exhibited optical absorption in the visible region, high minority carrier mobility, and large diffusion in length, rendering this material a promising candidate for solar cells. Based on these findings, we designed and implemented an ACdTS absorber in a thin-film solar cell (TFSC) structure. The new kesterite solar cell has a high efficiency of 11.6% with a low deficit in the output voltage. Moreover, a strategic combination between the particle swarm optimization approach and the ACdTS TFSC decorated with periodic nanowires is proposed to obtain significantly improved photovoltaic characteristics. The optimized design identifies a new pathway for a high conversion efficiency of 14%, far surpassing that provided by the conventional TFSC kesterite.

Tunnel FETisone of thealternativedevicefor low power electronics having steep subthreshold swing and lower leakage current than conventional MOSFET. In this research work, we have implemented the idea of high -k gate dielectric ondouble gate Tunnel FET, DG-TFETfor improvement of device features.An extensive investigation for the analog/RF and linearity feature of DG-TFET has been donehere for low power circuit and system development.Several essential analog/RF and linearity parameters like transconductance(gm), transconductance generation factor (gm/IDS) its high-order derivatives (gm2, gm3), cut-off frequency (fT), gain band width product (GBW), transconductance generation factor (gm/IDS) has been investigated for low power RF applications.The VIP2, VIP3, IMD3, IIP3, distortion characteristics (HD2, HD3), 1- dB the compression point, delay and power delay product performancehave also been throughly studied.It has been observed that the device features discussed for circuitry applications are found to be sensitiveto of gate materials, design configuration and input signals.

Tunnel FET is one of the promising devices advocated as a replacement of conventional MOSFET to be used for low power applications. Temperature is an important factor affecting the performance of circuits or system, so temperature associated reliability issues of double gate Tunnel FET and its impact on essential circuit design components have been addressed here. The temperature reliability investigation is based on double gate Tunnel FET, containing Si_1-xGe _x /Si, source/channel and HfO₂ high-k gate dielectric material. During investigation, it has been found that at high temperature application range ~ 300 K - to - 600 K,the Tunnel FET device design parameters exhibit weak temperature dependency with switching current (I_ON), while the off-state current (I_OFF) is slightly varying ~10⁻¹⁷A/μm-to-10⁻¹⁰A/μm. In addition, the impact of temperature on various device design element such as V_TH(i.e.,switching voltage),on-current (I_ON), off-current (I_OFF), switching ratio (I_ON/I_OFF) and average subthreshold slope (i.e., SS_avg), ambipolar current (I_AMB) have been done in this research work.The essential circuit design components for digital and analog/RF applications, such as current amplification factor(g_m) and its derivative (g_m’),the C-V components of device design, Cgg, Cgd and C_gs, cut - off frequency (ƒ_T) and gain band width (GBW) product have deeply investigated. In conclusion, the obtained results show that the designed double gate Tunnel FET device configuration and its circuit design components are suitable for ultra-low power circuit,system applications and reliable for hazardous temperature environment.

The development of CZTS-based solar cells is limited by two factors, the low open circuit voltage and the conversion efficiency. This is why, in this study, the impact of Cu2ZnSnS4 (CZTS) absorber thin layer parameters on the performance of the proposed MoS2/CZTS/CdS/ZnO heterostructure is simulated by the standard software SCAPS-1D. The improving output performances of this structure; the open circuit voltage (Voc), the short circuit current density (Jsc), the fill factor (FF) and the efficiency (h) are obtained by varying the absorber layer thickness, acceptor carrier concentration NA and taking into account the effect of the electron work function of the back metal contact. The optimized cell provides an energy conversion efficiency of 15.23% (Voc = 0.99 V, Jsc = 21.89 mA/cm2, FF = 69.79%) for an optimal thickness of 2 μm, a doping of 1×1016 cm-3. Performance enhancement of the proposed solar cell is subject to the back metal contact, the optimal simulated value of 5.7 eV of which represents that of the Platinum’s work function Pt. The interest of this simulation makes it possible to adjust the solar cells dimensions, optimize the absorbent layers doping, choose appropriately the back metal contact and therefore help to considerably reduce the various recombination phenomena as well as the secondary phases.