A monolithic electrically injected InGaN/GaN disk-in-nanowire (λ=533nm) laser on (001) silicon

The field of silicon photonics is becoming more important due to the ever-increasing data rates of modern computers [1]. While silicon lends itself well to the monolithic inegration of high quality modulators, detectors, and waveguides, it remains very challenging to acheive high quality light emission for use in silicon photonics. As yet, there have been three main approaches to providing silicon photonics light sources: InGaAs/GaAs-based quantum well and quantum dot lasers emitting in the 1.0-1.3 μm range, grown on tilted-plane [(001)→4° toward (111)] silicon [2, 3, 4]; III-V based lasers grown separately and bonded to silicon [5]; and growth using novel buffer layers and strained Ge on Si [6, 7]. Each of these approaches is not without its drawbacks. Structures grown on tilted or misaligned silicon wafers are incompatible with most standard CMOS processes, and their high density of lattice mismatch-induced dislocations renders their reliability suspect. Bonded III-V devices eliminate the process advantages of monolithic integration by requiring an off-chip growth and bonding process. III-N nanowire and disk-in-nanowire (DNW) structures can be grown relatively defect free directly on (001) silicon substrates [8]. Nanowires grow in the wurtzite structure along the c-plane. Silicon-grown nanowire structures are radially strain-relaxed during growth, leading to a lower polarization field than that of comparable indium composition quantum wells. Using these InGaN/GaN DNW structures, devices emitting in the 400-700 nm range have been grown and fabricated on (001) silicon substrates [9]. Here we report for the first time a room temperature, electrically injected, monolithic InGaN/GaN DNW green (λ = 533 nm) edge-emitting laser on (001) silicon. By varying the indium composition of the active region InGaN disks, laser emission at longer and shorter wavelengths should be possible as well.