Trapping Electrons in Semiconductors: Explained

[madmike159]

I heard about a effect in semiconductors where you can trap a electron in a 2d plane. If you have a semiconductor inbetween a semiconductor of a higher band gap it creats a quantom well where the electron gets trapped. I guess because its not moving it has no defined position so it could exsist in the second dimension. Could some one please explain this in a bit more detail (if its even real).

Thanks

 

[f95toli]

This is know as a 2DEG (2D electron gas) and it is definately real, there are plenty of devices that use 2DEGs in various ways.
Note that the electron is not really trapped in 2 spacetime dimensions, the "2" is due to the fact that it is confined to a layer which is much thinner than all relevant lengt-scales (e.g. its mean-free path) which means that all the relevant physics becomes two-dimensional (in very thin wires the physics becomes 1D and in small dots 0D).

 

[charng]

The phenomenon you are referring to is known as quantum confinement and it is indeed a real effect in semiconductors. When a semiconductor material is sandwiched between two layers of a semiconductor with a higher band gap, it creates a potential well that traps the electrons in a two-dimensional plane. This is because the electrons are confined to a smaller space and their energy levels become quantized, meaning they can only exist at certain discrete energy levels within the well.

This trapping of electrons has important implications in the field of nanotechnology and can be utilized in devices such as quantum dots, which are tiny semiconductor particles that can emit light at specific wavelengths due to the confinement of electrons.

To understand this in more detail, we need to look at the energy levels of electrons in a semiconductor. In a bulk semiconductor, the electrons have a continuous range of energy levels, but when confined to a smaller space, their energy levels become discrete. This is due to the wave-like nature of electrons, where their wavelength is inversely proportional to their momentum. In a confined space, the electrons have limited momentum and therefore, have a longer wavelength, resulting in quantized energy levels.

The trapping of electrons in a 2D plane occurs due to the potential well created by the two layers of higher band gap semiconductors. The electrons are attracted to the well and become trapped within it, unable to escape due to the energy barrier created by the higher band gap layers.

In summary, trapping electrons in semiconductors through quantum confinement is a real and well-studied phenomenon with important applications in nanotechnology. It is a result of the wave-like nature of electrons and the creation of a potential well in a confined space. I hope this explanation helps to clarify the concept for you.