Electrically injected GaN-on-Si blue microdisk laser diodes

Abstract

III-nitride blue microdisk laser diodes are highly desirable in emerging applications, such as augmented reality, virtual reality, and visible light communication. However, the electrically pumped blue microdisk lasers have been lagging for decades owing to weak optical confinement and large internal absorption loss. In this study, the waveguide layers and cladding layers were carefully engineered to enhance the optical confinement and reduce internal absorption loss. Therefore, the first electrically injected blue microdisk laser diodes grown on Si substrates have been successfully fabricated, and exhibited a resistor-capacitance-limited bandwidth of 24.1 GHz, showing highly promising applications in high-speed and large-modulation-bandwidth visible light communication.

Continuous-Wave Current Injected InGaN/GaN Microdisk Laser on Si(100)

“…Based on this, the thermal resistance can be determined to be 95 K/W, which is 32.5% less than that of our conventional 20 μm radius GaN-based microdisk laser on Si(111) substrates, mainly due to the largely reduced thickness of the AlGaN layer with a very low thermal conductivity. As compared with our previous GaN-based microdisk laser on Si(111), − the 0.7 μm thick high-Al-content AlGaN multilayer buffer was completely removed, and the thickness of AlGaN CL was shorten from 1.3 to 0.5 μm in the heat dissipation path. Both of which contributed the sharply reduced thermal resistance.…”

“…To design the laser structure, the optical simulation of the GaN-based microdisk laser was performed by the finite-difference time-domain method. , In the simulation, the optical absorption coefficient and refractive index of each epitaxial layer were set as those reported in literatures, − and then the optical confinement factor (OCF) of each epitaxial layer could be determined. The total OCF of the laser (Γ) is the sum of OCFs of three QWs, and the product of absorption coefficient and OCF for each layer adds up to the total internal absorption loss (α i ).…”

“…Si photonics are deemed as a prospective way to exceed the limitations of speed and bandwidth and then revolute the communication technology. − Since indirect bandgap Si has low luminous efficiency, highly efficient light sources are urgently required and widely studied. GaN-based microdisk laser is characterized with small mode volume, low power consumption, high modulation rate, easily coupled output, and wide emission spectra ranging from 200 to 1870 nm. − GaN-based microdisk laser on Si can be operated as an efficient on-chip laser source together with GaN-based waveguide or parametric down conversion technology. − ,− Additionally, it can be also used in single photon sources, ion trapping, biosensing, cavity quantum electrodynamics, and visible light communication. ,,, Therefore, GaN-based microdisk laser on Si has received great attentions and been extensively studied. − …”

“…Recently, we have demonstrated the first electrically pumped lasing of GaN-based microdisk laser grown on Si substrate at room temperature. − However, it is integrated on Si(111), which is normally used to epitaxially grow GaN-based materials, − , but not fully compatible with CMOS-used Si(100). To make full use of cost-effective mainstream CMOS process, it is worthwhile to achieve GaN-based microdisk laser on Si(100).…”

“…4−6,9−14 Additionally, it can be also used in single photon sources, ion trapping, biosensing, cavity quantum electrodynamics, and visible light communication. 6,7,9,13 Therefore, GaN-based microdisk laser on Si has received great attentions and been extensively studied. 4−15 Recently, we have demonstrated the first electrically pumped lasing of GaN-based microdisk laser grown on Si substrate at room temperature.…”