Deep‐Ultraviolet Micro‐LEDs Exhibiting High Output Power and High Modulation Bandwidth Simultaneously

Abstract Deep‐ultraviolet (DUV) solar‐blind communication (SBC) shows distinct advantages of non‐line‐of‐sight propagation and background noise negligibility over conventional visible‐light communication. AlGaN‐based DUV micro‐light‐emitting diodes (µ‐LEDs) are an excellent candidate for a DUV‐SBC light source due to their small size, low power consumption, and high modulation bandwidth. A long‐haul DUV‐SBC system requires the light source exhibiting high output power, high modulation bandwidth, and high rate, simultaneously. Such a device is rarely reported. A parallel‐arrayed planar (PAP) approach is here proposed to satisfy those requirements. By reducing the dimensions of the active emission mesa to micrometer scale, DUV µ‐LEDs with ultrahigh power density are created due to their homogeneous injection current and enhanced planar isotropic light emission. Interconnected PAP µ‐LEDs with a diameter of 25 µm are produced. This device has an output power of 83.5 mW with a density of 405 W cm⁻² at 230 mA, a wall‐plug efficiency (WPE) of 4.7% at 155 mA, and a high −3 dB modulation bandwidth of 380 MHz. The remarkable high output power and efficiency make those devices a reliable platform to develop high‐modulation‐bandwidth wireless communication and to meet the requirements for bio‐elimination.