What is band offset in semiconductor?

What is band offset in semiconductor?

The band offset is defined simply as the discontinuity in the band edge at the interface between two semiconductors. A number of current theories seem to yield band offset values in reasonable agreement with experiment, even though the physical ideas underlying these theories can be quite different.

How is conduction band offset calculated?

Conduction band offset is by definition the difference in the electron affinity of the two materials. That is Delta Ec= X2-X1, where X2 and X1 are the electron affinities of the two materials 2 and 1.

What is staggered band alignment?

The conduction band of the smaller-gap material might lie above that of the larger-gap material, or its valence band might lie below that of the larger-gap material. Such a band alignment is called staggered, and is known to occur in the In Ga As-GaAs Sb system [26], as well as those of Figures 7 and 10.

What is meant by band offsets?

Band offset describes the relative alignment of the energy bands at a semiconductor heterojunction.

What is bandgap voltage offset?

Band gap-voltage offset is shown experimentally to be largely independent of band gap Eg for a wide range of metamorphic and lattice-matched semiconductors from 0.67 to 2.1 eV.

What is band gap alignment?

The heterojunction band gap alignment can be determined by the so called band offset ratio defined for conduction band edge as. (9.13) where ΔEC is the discontinuity in the conduction band (CB) between the two materials and ΔEVHH is the discontinuity in the heavy-hole valence band (VB).

What is band offset in semiconductor devices?

The determination of the energy difference of conduction or valence bands across a semiconductor heterojunction, or band offset, is an important aspect of heterojunction characterization, and ultimately of device performance.

How do you determine the band offset?

The band offsets can be determined by both intrinsic properties, that is, determined by properties of the bulk materials, as well as non-intrinsic properties, namely, specific properties of the interface.

What is the band offset between the oxide and Si?

The band offset between the oxide and Si defines the barrier for injection of electrons or holes into the oxide bands. The CB offset tends to be the smaller of the two. The CB offset is one of the key criteria in the selection of a gate oxide. It must be >1 eV to provide adequately low leakage current ( Robertson, 2000 ).