Optoelectronic Smart Pixels Monallithically Integrated

A layer structure, grown in a single step, and a fabrication process were developed for the monolithic integration of AlGaAs/GaAs optoelectronic smart pixels. Metal semiconductor field-effect transistors (MESFETs), light-emitting diodes (LEDs) and photodiodes (PDs) were designed in such a way that the light emitted from the LEDs can efficiently be detected by the PDs. An example is presented of a fabricated optoelectronic smart pixel: a threshold circuit consisting of a dual-photodiode differential input, an inverter and a current-balanced output containing an LED. The circuit shows a switching energy of 2 pJ. The minimum switching power is <1 nW with a contrast ratio >1000. The maximum light output of the LED is 18 mu W With an overall power dissipation of 20 mW.