The development of compact models for double-gate (DG) MOSFETs and FinFETs necessary in circuit simulators is an important research field, which allows the efficient practical characterization of these devices, as well as their application in analog circuit design. In this paper we review and assess different approaches for developing core and complete compact models for DG MOSFETs and FinFETs.

Water incorporation in an electrolyte solution has become a popular method for increasing the photoconversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Although the PCE enhancement in DSSCs has been associated with incorporation of a precise amount of water, the fundamental mechanisms underlying such an enhancement remain unclear. Enhanced photocurrent in aqueous electrolyte DSSCs has also been linked to band-edge shifting, which leads to higher electron injection efficiencies. From X-ray absorption fine-structure spectroscopy (XAFS) of TiO 2 electrodes of dismantled DSSCs and electrodynamical characterization of the assembled aqueous DSSCs, we show that a less static disordered (lowest Debye−Waller value) and more relaxed lattice (interatomic distances comparable to bulk TiO 2 ) are the fingerprints for the optimized aqueous DSSC. On the other hand, lower efficiency of aqueous DSSCs is associated with a more static disordered (higher Debye−Waller values compared to the optimal aqueous DSSC) and less relaxed lattice (lower interatomic distances compared to bulk TiO 2 ). For the optimum amount of water, small perturbation-based stepwise light-induced transient measurements of the photocurrent of the operational DSSCs revealed a decrease in the overall trap density in the intragap states of the TiO 2 electrode. The decrease in intragap states induces a downward shift of the quasi-Fermi level, which is responsible for the short-circuit photocurrent amplification. The findings of this study establish a direct link between the structural parameters such as the interatomic distance and the Debye−Waller factor with electrodynamical and photovoltaic parameters such as the total trap density and PCE for the electrodes used in aqueous DSSCs, paving the way for research into more stable and environmentally friendly solar cells.

No abstract

The development of models to simulate circuits containing new devices is an important task to allow the introduction of these devices in practical applications. In this paper we show the advantages of using the recently developed Symmetric Doped Double-Gate Model as already introduced in SmartSpice simulator, for modeling circuits containing Double-Gate Graded-Channel (GC) transistors. In this case there is no need to use two different models to represent the graded-channel device, as has been done up to now. Current-mirror circuits using GC devices have been simulated and the results were validated comparing them with those obtained using the MIXED-MODE module of two-dimensional numerical ATLAS simulator of the GC devices.