Room-temperature electroluminescence and light detection from III-V unipolar microLEDs without p-type doping

Abstract

The twentieth-century semiconductor revolution began with “man-made crystals,” or p-n junction-based heterostructures. This was the most significant step in the creation of light-emitting diodes (LEDs), lasers, and photodetectors. Nonetheless, advances where resistive p-type doping is completely avoided could pave the way for a new class of n-type optoelectronic emitters and detectors to mitigate the increase of contact resistance and optical losses in submicrometer devices, e.g., nanoLEDs and nanolasers. Here, we show that nanometric layers of AlAs/GaAs/AlAs forming a double-barrier quantum well (DBQW) arranged in an n-type unipolar micropillar LED can provide electroluminescence (EL) (emission at 806 nm from the active DBQW), photoresponse (responsivity of 0.56 A/W at 830 nm), and negative differential conductance (NDC) in a single device. Under the same forward bias, we show that enough holes are created in the DBQW to allow for radiative recombination without the need of p-type semiconductor-doped layers, as well as pronounced photocurrent generation due to the built-in electric field across the DBQW that separates the photogenerated charge carriers. Time-resolved EL reveals decay lifetimes of 4.9 ns, whereas photoresponse fall times of 250 ns are measured in the light-detecting process. The seamless integration of these multi-functions (EL, photoresponse, and NDC) in a single microdevice paves the way for compact, on-chip light-emitting and receiving circuits needed for imaging, sensing, signal processing, data communication, and neuromorphic computing applications.