Low noise, high detectivity polarization sensitive room temperature infrared photodetectors based on Ge quantum dots decorated Si-on-insulator nanowire field effect transistors.

A CMOS compatible infrared (1200 - 1700 nm) detector based on Ge-quantum dots decorated on single Si-nanowire channel on silicon-on-insulator (SOI) platform with a superior detectivity at room temperature is presented. The spectral response of a single nanowire device measured in aback gated field-effect transistor geometry displays a very high value of peak detectivity ~ 9.33 × 1011Jones at ~1500 nm with a relatively low dark current (~ 20 pA), which are attributed to the fully depleted Si nanowire channel on SOI substrates. The noise power spectrum of the devices exhibits a 1/, with the exponent, γ showing two different values of 0.9 and 1.8 owing to mobility fluctuations and generation-recombination of carriers, respectively. Ge QDs decorated nanowire devices exhibit a novel polarization anisotropy with a remarkably high photoconductive gain of ~104. The superior performance of Ge-QDs/Si nanowire phototransistor in infrared wavelengths is potentially attractive to integrate electro-optical devices into Si for on-chip optical communications.