Heterogeneously integrated organic light-emitting diodes with complementary metal-oxide-silicon circuitry

Top-emitting arrays of organic light-emitting diodes (OLEDs) have been fabricated and demonstrated on complementary metal-oxide-silicon (CMOS) circuitry. The 8 × 8 array of OLEDs is composed of 90 μm micropixels with a 55 μm separation. The OLEDs are based on an emitting layer of tris-(8-hydroxyquinoline)aluminum (Alq₃) doped with coumarin 6 to provide green light emission. A layer of N,N′-diphenyl-N, N′-bis(3-methylphenyl)1-1′-biphenyl 1-4, 4′-diamine (TPD) was used as a hole transport layer and poly(ethylenedioxythiophene) doped with polystyrenesulfonate was used as a buffer layer between the TPD and the CMOS anode metal. Bright light was emitted through a semitransparent Mg:Ag cathode when the micropixel was driven by an individual current source.