Growth and optical properties of type-II InP/GaAs self-organized quantum dots

Self-organized InP quantum dots having a staggered band lineup (type II) are formed in a GaAs matrix by metalorganic chemical vapor deposition. Strong photoluminescence centered at 986 nm is observed for the sample of InP grown at 490 degreesC, which can be attributed to radiative recombination of zero-dimensional (0D) electrons located in the InP dots and holes located in the surrounding regions. The indirect recombination of photogenerated carriers has been confirmed by the measurement of luminescence at different excitation densities and temperatures. If the InP is grown at 600 degreesC, experimental results show that a thicker and much smoother wetting layer is formed which results in much stronger and narrower luminescence located at 875 nm. In addition, state filling of the 0D electrons is also observed for the type-II quantum dots. (C) 2001 American Institute of Physics.