Tilted-charge high speed (7 GHz) light emitting diode

We demonstrate a higher speed form of light emitting diode (LED), an asymmetrical two-junction tilted-charge LED, utilizing an $n$-type buried “drain” layer beneath the $p$-type “base” quantum-well (carrier and photon) active region. The drain layer tilts and pins the charge in the manner of a heterojunction bipolar light emitting transistor (HBLET), selecting and allowing only “fast” recombination (recombination lifetime $τB$ of the order of base transit time $τt$⁠). The tilted-charge LED, simple in design and construction, is capable of operation at low current in spontaneous recombination at a 7 GHz bandwidth or even higher with more refinement.