Photoluminescence sensitivity to methanol vapours of surface InP quantum dot: effect of dot size and coverage

We investigate the effect of morphology and coverage of self-assembled epitaxial InP quantum dot on the photoluminescence sensitivity to methanol vapour. The photoluminescence of quantum dots is in the near infrared (750–900 nm) for quantum dot height and lateral size of 2–3 nm and 20–30 nm, respectively. Photoluminescence intensity undergoes an enhancement when the samples were exposed to methanol vapours. The dimension, density and effective surface of quantum dots have been estimated by statistical analysis of the dot morphology based on atomic force micrographs. We observed that it is possible to increase the magnitude of the intensity change due to methanol vapour by tailoring quantum dot size and density to increase the sample coverage. We observe a linear dependence on the coverage of the luminescence intensity changes induced by exposition to methanol vapours.