257-nm AlGaN-Based Deep Ultraviolet Light-Emitting Diodes With Thin Quantum Wells to Achieve Large −3 dB Bandwidth

In this work, an AlGaN-based deep ultraviolet light-emitting diode (DUV LED) with ultra-thin quantum wells has been proposed to improve the −3dB bandwidth for the potential use in non-line-of-sight communication. Simulation results demonstrate that the ultra-thin quantum well structure effectively suppresses the quantum-confined Stark effect (QCSE), promotes uniform hole distribution and radiative recombination. Consequently, this results in shortened radiative recombination lifetime <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\tau _{\textit {ra}{d}})$ </tex-math></inline-formula>, which generates a high −3 dB modulation bandwidth of 194 MHz and maintains a signal-to-noise ratio (SNR) above 10 dB in the low-frequency regime for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$350~\mu $ </tex-math></inline-formula>m <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 350~\mu $ </tex-math></inline-formula>m DUV LED. Moreover, the fabricated devices exhibit a low leakage current of less than 10 nA at the reverse bias of −5 V, indicating that leakage paths caused by mesa sidewall defects are significantly reduced.