We investigate sub-bandgap absorption in pyrite FeS 2 single-crystals, using both natural and synthetic crystals. Both types of crystals show non-negligible magnitudes of sub-bandgap absorption. To test whether the origin of the residual sub-bandgap absorption is partially due to a lower bulk bandgap than previously thought, we conduct temperature-dependent electrical measurements on natural an...

Amorphous semiconductors are materials with a brilliant prospect for a wide range of optical applications like solar cells, optical sensors, optical devices, and memories. The purpose of the present research was to study the semiconducting optical properties of SiO2-Al2O3-CaF2 and SiO2-Al2O3-BaF2 oxyfluoride...

We report the fabrication and characterization of a new type all-solid photonic bandgap fiber. By introducing an index depressed layer around the high-index rod in the unit cell of photonic crystal cladding, transmission loss as low as 2 dB/km within the first bandgap is realized for the all-solid photonic bandgap fiber with a bandwidth of over 700 nm. The bend loss experiment shows that the ph...

Graphene oxide nanoribbons (GONRs) are wide bandgap semiconductors that can be reduced to metallic graphene nanoribbons. The transformation of GONRs from their semiconductive to the metallic state by annealing has attracted significant interest due to its simplicity. However, the detailed process by which GONRs transform from wide-bandgap semiconductors to semimetals with a near zero bandgap is...

The noise power of bandgap references is directly related to the current consumption of the bandgap reference. This paper describes the design of low-noise bandgap references. It is shown that for an idealized bandgap reference, a fundamental noise limit exists when the limited current consumption is a constraint. A design example is given of a 1 V bipolar bandgap reference with a current consu...

Securing a semiconducting bandgap is essential for applying graphene layers in switching devices. Theoretical studies have suggested a created bulk bandgap in a graphene layer by introducing an asymmetry between the A and B sub-lattice sites. A recent transport measurement demonstrated the presence of a bandgap in a graphene layer where the asymmetry was introduced by placing a graphene layer o...

In this paper, we have examined the conductivity and interaction studies of ammonium and imidazolium based ionic liquids (ILs) with the newly synthesised low bandgap polymer (Poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole) (PHVTT)). Use of low bandgap polymers is the most suitable way to harvest a broader spectrum of solar radiations for solar cells. But, still there is lack of most efficient l...

Traditional bandgap based current references have restricted temperature operating range due to the limited input common mode range of the feedback amplifier. This paper introduces a modified bandgap current reference that overcomes this limitation by placing a natural device (V, -0V) level shift stage between the amplifier and the bandgap. The circuit has been fabricated in a 0.25-pm CMOS proc...

We demonstrate one-dimensional optically-induced photonic lattices with a negative defect and observe linear bandgap guidance in such a defect. We show that a defect mode moves from the first bandgap to a higher bandgap as the lattice potential is increased. Our experimental results are in good agreement with the theoretical analysis of these effects.