micro-light emitting diode (µLED) array sharing a common p-electrode (anode), and with individually
addressable n-electrodes (cathodes). Compared to conventional GaN-based LED
arrays, this array design employs a reversed structure of common and individual electrodes,
which makes it innovative and compatible with n-type metal-oxide-semiconductor (NMOS)
transistor-based drivers for faster modulation. Excellent performance characteristics are illustrated
by an example array emitting at 450 nm. At a current density of 17.7 kA/cm2 in
direct-current operation, the optical power and small signal electrical-to-optical modulation
bandwidth of a single µLED element with 24 µm diameter are over 2.0 mW and 440 MHz,
respectively. The optimized fabrication process also ensures a high yield of working µLED
elements per array and excellent element-to-element uniformity of electrical/optical characteristics.
Results on visible light communication are presented as an application of an array
integrated with an NMOS driver. Data transmission at several hundred Mb/s without bit error
is achieved for single- and multiple-µLED-element operations, under an ON–OFF-keying
modulation scheme. Transmission of stepped sawtooth waveforms is also demonstrated to
confirm that the µLED elements can transmit discrete multilevel signals.