Growth of nitride-based light emitting diodes with a high-reflectivity distributed Bragg reflector on mesa-patterned silicon substrate.

(Ga,In)N/GaN multiple quantum well blue light emitting diodes (LEDs) grown on mesa-patterned silicon substrates with improved electro-optic characteristics are demonstrated. The active regions are grown on top of high-reflectivity AlN/(Al,Ga)N distributed Bragg reflectors (DBRs). Due to efficient stress relaxation at the mesa edges, crack formation during growth or upon the post-growth cooling-down of the samples can be avoided. A large number of AlN/(Al,Ga)N bilayers in the DBR can be then included in the LED structures leading to strong enhancement of the LED device output power in spite of the presence of the absorbing silicon substrate at the LED emission wavelength. Photograph of a blue light emitting diode ( I = 20 mA) grown on top of a high reflectivity distributed Bragg reflector on a mesa-patterned silicon substrate. [ABSTRACT FROM AUTHOR]