A Novel Monolithic Integration of Light-Emitting HEMT with InGaN Quantum Well Insertion Performing as Optoelectronic Devices

Visible light communication (VLC) technology based on GaN light emitting diode (LED) has been widely studied because of its wide bandwidth and high reliability. However, low integration is one of the main factors limiting the development of VLC technology at present. This study reports a novel GaN-based light emitting diode-high electron mobility transistor (LED-HEMT) monolithically integrated device. The light efficiency is improved not only by adding InGaN quantum well layer at the AlGaN/GaN interface, but also thin Ni/Au layer is used as a substitute for the traditional indium tin oxide (ITO) layer to realize the current expansion function, so that the device has faster switching speed and reliable light modulation ability. The influence of gate-source voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf>) and applied drain voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</inf>) on the control capability of LED-HEMT was studied. The integrated LED-HEMT exhibited output current can reach 309 mA/mm when the HEMT was modulated with V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</inf> = 14 V and V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> = 2 V, which driving capability is better to previous Si-based MOSFETs, demonstrating good output performance. The peak of the emission spectrum is at 445 nm when I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ds</inf>= 15 mA. This work offers a novel approach to the monolithic integration of LED-HEMT and provides reference for the application of Micro-LED in the fields of visible light communication and optoelectronic detection.