Non-Equilibrium Green´s Function Calculation of Optical Absorption in Nano Optoelectronic Devices

The high speed of optical devices motivates the integration between electronics and photonics. One of the most common optoelectronic devices used for such integration is a photodetector. This paper describes the formulation of an optical absorption inside a photodetector using the non-equilibrium Green´s function (NEGF) framework. To illustrate the use of the formulation, optical properties of a double barrier quantum well photodetector are simulated. The photocurrent and the spectral response of the photodetector are calculated and presented. We also study the effect of varying various bias voltage and introducing non-uniformity in the effective mass. It is found that the peak locations do not change significantly under these variations.