# Mass of a hole

## Main Question or Discussion Point

How can the mass of a hole is larger than an electron?I want to know what a hole signifies and the mass energy required for it to propagate in the semiconductors for constituting current.

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ZapperZ
Staff Emeritus
How can the mass of a hole is larger than an electron?I want to know what a hole signifies and the mass energy required for it to propagate in the semiconductors for constituting current.
Back up a bit. Do you know how an effective mass in define in terms of the band dispersion? You have not provided enough information on what you DO know.

Zz.

no.I haven't got any idea about effective mass.I know that a hole is just the empty space created by an electron.and I have a little idea about band dispersion.

sir,please help me out with some simple lines that i can understand without knowing much of quantum physics.

DrDu
The point is that not only a hole has an (effective) mass different from that of an electron but that also the effective mass of an electron in a semiconductor is different from the mass of a free electron. The reason is that an electron or a hole in a semi-conductor is a quasi-particle. I.e. it is a compound object consisting of an electron (or hole) that carries deformations of the lattice with him and also interacts with the "sea" of other electrons. These deformation etc. increase inertia and hence the apparent or "effective" mass of that quasi-particle.
Another contribution to the mass comes from increasing reflection from lattice planes in the crystal near the zone boundaries.

Thank you sir,but i didn't get the last line.would you mind explaining me once more?and the increasing inertia increases the effective mass of only hole or only electron or both?

ZapperZ
Staff Emeritus