Photoluminescence Studies of Single Submonolayer InAs Structures Grown on GaAs (001) Matrix

We report a detailed analysis of optical properties of single submonolayer InAs structures grown on GaAs(001)matrix.It is shown that the formation of InAs dots with 1 monolayer(ML)height leads to localization of exciton under certain submonolayer InAs coverage,which play a key role in the highly improved luminescence efficiency of the submonolayer InAs/GaAs structures.