Wide Bandgap Semiconductors - Material Properties - Bandgap


The magnitude of the coulombic potential determines the bandgap of a material, and the size of atoms and electronegativities are two factors that determine the bandgap. Materials with small atoms and strong, electronegative atomic bonds are associated with wide bandgaps. Smaller lattice spacing results in a higher perturbing potential of neighbors.

Elements high on the periodic table are more likely to be wide bandgap materials. With regard to III-V compounds, nitrides are associated with the largest bandgaps, and, in the II-VI family, oxides are generally considered to be insulators.

Bandgaps can often be engineered by alloying, and Vegard's Law states that there is a linear relation between lattice constant and composition of a solid solution at constant temperature.

The position of the conduction band minima versus maxima in the band diagram determine whether a bandgap is direct or indirect. Most wide bandgap materials are associated with a direct bandgap, with SiC and GaP as exceptions.

Read more about this topic:  Wide Bandgap Semiconductors, Material Properties

Other articles related to "bandgap, bandgaps":

Shockley–Queisser Limit - Exceeding The Limit - Photon Upconversion
... As discussed above, photons with energy below the bandgap are wasted in ordinary single-junction solar cells ... incorporating into the module a molecule or material that can absorb two or more below-bandgap photons and then emit one above-bandgap photon ...
Bandgap Voltage Reference
... A bandgap voltage reference is a temperature independent voltage reference circuit widely used in integrated circuits, usually with an output voltage around 1.25 V, close to the theoretical 1.22 ...
Thermophotovoltaic - Active Components and Materials Selection - Photovoltaic Cells - Indium Gallium Arsenide
... When lattice-matched to an InP substrate, InGaAs has a bandgap of 0.74 eV, which is not an improvement on traditional GaSb ... However, to absorb higher wavelength photons, the bandgap may be engineered by changing the ratio of In to Ga ... The range of bandgaps for this system is from about 0.4 to 1.4 eV ...
Multijunction Photovoltaic Cell - Description - Increasing Efficiency
... situation only exists if one considers a material with a single bandgap ... If you build a cell with multiple bandgaps, and tune each one to a different wavelength, then it is possible to capture the energy that would otherwise be lost ... For instance, if one had a cell with two bandgaps in it, one tuned to red light and the other to green, then the extra energy in green, cyan and blue light would be lost only ...