Photocurrent Spectroscopy Of Site-Controlled Pyramidal Quantum Dots

Intraband photocurrent spectroscopy of site-controlled pyramidal quantum dots by inserting them into the intrinsic region of n-i-n like quantum dot infrared photodetector structure is reported. The photovoltaic response is observed in the mid-infrared region. A peak responsivity of 0.4 mA/W at 120meV (lambda = 10 mu m) is observed at 10K at -2 V bias. The ability to engineer states in the conduction band of the QDs has been exploited to tune their photocurrent response from 10 mu m to 18 mu m with a narrow spectral width of Delta lambda/lambda = 0.17. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737426]