P-type doping of wide-bandgap semiconductors has long been a challenging issue for the relatively large activation energy and strong compensation of acceptor states in these materials, which hinders their applications in ultraviolet (UV) optoelectronic devices drastically. Here we show that by employing electrostatic doping method, hole-dominant region can be formed in wide bandgap semiconducto...

The potentiality of millimter-wave (mm-wave) double-drift region (DDR) impact avalanche transit time (IMPATT) diodes based on a wide bandgap (WBG) semiconductor material, Gallium Phosphide (GaP) has been explored in this paper. A non-sinusoidal voltage excited (NSVE) large-signal simulation method has been used to study the DC and high frequency characteristics of DDR GaP IMPATTs dsigned to ope...

We have performed a comprehensive first-principles study of the electronic and magnetic properties of two-dimensional (2D) transition-metal dichalcogenide (TMD) heterobilayers MX2/MoS2 (M = Mo, Cr, W, Fe, V; X = S, Se). For M = Mo, Cr, W; X = S, Se, all heterobilayers show semiconducting characteristics with an indirect bandgap with the exception of the WSe2/MoS2 heterobilayer which retains the...

Compared to the long history of plasmonic gratings, there are only a few studies regarding the bandgap in the propagation of plasmonic surface waves. Considering the previous studies on interpretation of plasmonic bandgap formation, we discuss this phenomenon using the effect of both surface plasmon polariton (SPP) and localized surface plasmon (LSP) for our fabricated one-dimensional metallic-...

We present a conceptual approach to low bandgap copolymers, in which we clarify the physical parameters which control the optical bandgap, develop a fundamental understanding of bandgap tuning, unify the terminology, and outline the minimum requirements for accurate prediction of polymer bandgaps from those of finite length oligomers via extrapolation. We then test the predictive power of sever...

On the basis of a tight binding model we reveal how the bandgap in bilayer graphene antidot lattices (GALs) follows a different scaling law than in monolayer GALs and we provide an explanation using the Dirac model. We show that previous findings regarding the criteria for the appearance of a bandgap in monolayer GALs are equally applicable to the bilayer case. Furthermore, we briefly investiga...

The photonic bandgap of magneto-optical (MO) photonic crystals (PhCs) induced by an external dc magnetic field is theoretically investigated with the plane-wave expansion method. The effect of PhC lattice shape, MO filling fraction and dc magnetic intensity on such type of bandgap has been studied. It is found that PhC with triangular lattice is superior to PhC with square lattice in term of ba...

In a low dropout (LDO) linear regulator whose reference voltage is supplied by a bandgap reference, double stacked diodes increase the effective junction area ratio in the bandgap reference, which significantly lowers the output spectral noise of the LDO. A low noise LDO with the area-efficient bandgap reference is implemented in 0.18 μm CMOS. An effective diode area ratio of 105 is obtained wh...

The development of medium-bandgap solar cell absorber materials is of interest for the design of devices such as tandem solar cells and building-integrated photovoltaics. The recently developed perovskite solar cells can be suitable candidates for these applications. At present, wide bandgap alkylammonium lead bromide perovskite absorbers require a high-temperature sintered mesoporous TiO2 phot...

We present here a variational method for maximizing the bandgap in a one-dimensional system where the potential is subject to given constraints. Two specific examples are studied in detail. In the first, we show that if the potential is constrained to lie between two values, the largest bandgap is obtained by a mixture of the highest and lowest potential an exact result valid in any dimension. ...