Capping layer in semiconductor quantum dot fabrication

[ubergewehr273]

TL;DR Summary

Why does a capping layer exist for semiconductor quantum dot fabrication.

Hi everyone,

I've been studying about semiconductor heterostructures and in particular quantum dots. I was wondering, why is there a need to have a "capping" layer above the layer where the quantum dots are formed within a sample?

Thanks in advance!

 

[f95toli]

I don't know what you have been reading; but you don't need a capping layer to make a semiconductor QD. However, depending on the fabrication process, the materials used, the technology, the geometry etc there might be very good reasons for you might end up using one.
But it is not a pre-requisite.