Increased normal incidence photocurrent in quantum dot infrared photodetectors

Abstract

We have increased the ratio of s-polarization (normal incidence) to p-polarization photocurrent to 50% in a quantum dot-in-a-well based infrared photodetector form the typical s-p polarization ratio about 20%. This improvement was achieved by engineering the dot geometry and the quantum confinement via post growth capping materials of the Stranski Krastanov growth mode quantum dots (QDs). The TEM images show that the height to base ratio of shape engineered QDs was increased to 8nm/12nm from the control sample's ratio 4nm/17nm. The dot geometry correlates with the polarized photocurrent measurements of the detector. © 2012 American Institute of Physics.