Single
photon is realized by the
luminescence of a single
quantum dot under ideal condition, so that the effective insulation of the single
quantum dot becomes very important. At present, InAs / GaAs
quantum dots which are used for manufacturing and realizing a
quantum dot single photon emission apparatus are obtained by a self-organized growth method, the InAs / GaAs quantum dots are distributed on a growth surface at random and have very high dot density, and several to hundreds of quantum dots are distributed on every square micron, so that the effective insulation of the single
quantum dot is comparatively difficult. Due to the randomicity of the distribution of the quantum dots on the growth surface, the positions of the quantum dots in an
optical microcavity become very hard to be controlled reliably. The invention prepares low-intensity InAs quantum dots by means of combining a
strain engineering theory with a pattern
underlay. The
strain engineering theory is as follows: during the process of growing multilayer quantum dots,
stress field action is produced due to the existence of underlayer quantum dots, and upper layer dots in the multilayer quantum dots tend to keep growing on the same position with the underlayer quantum dots in the vertical direction to form vertical matching. In addition, the
optical quality for growing the quantum dots on the pattern
underlay can be improved effectively just by a lamina GaAs
cushion layer with the thickness of tens of nanometers. The invention provides an MBE epitaxial method for positioning and growing a low-intensity InAs quanta dot by a
strain engineering theory and a pattern-
underlay combining technology, thus overcoming the randomicity for growing the quanta dot by the self-organized growth method and controlling the position and the density reliably. The method provides a reference measure for a method for preparing a quanta dot
single photon emission source.