Photoluminescence (PL) of near surface InAs quantum dots (QDs) has been stu
died as a function of the distance to the surface (30, 20, 10, 6 nm). We ob
serve a strong decrease in the QD PL intensity with decreasing barrier thic
kness. Nevertheless the QDs still show reasonably strong PL intensity even
when they are only 10 nm beneath the surface. After tile deposition of self
-assemble;I monolayers of octadecylthiol, we observe an increase ill PL int
ensity up to a factor of 1.87. Such an enhancement is attributed to a decre
ase in the density of surface states. This demonstrates that near surface I
nAs QDs ale very sensitive to changes of the surface conditions and the dep
osition of octadecylthiol monolayer may be used to increase, their sensitiv
ity which is promising toward future bio-sensor applications.