Nanolasers grown on silicon

Abstract

Here, we use a novel growth scheme to overcome this roadblock and directly grow on-chip InGaAs nanopillar lasers, demonstrating the potency of bottom-up nano-optoelectronic integration. Unique helically-propagating cavity modes are employed to strongly confine light within subwavelength nanopillars despite low refractive index contrast between InGaAs and silicon. These modes thereby provide an avenue for engineering on-chip nanophotonic devices such as lasers. Nanopillar lasers are as-grown on silicon, offer tiny footprints and scalability, and are thereby particularly suited to high-density optoelectronics. They may ultimately form the basis of the missing monolithic light sources needed to bridge the existing gap between photonic and electronic circuits. 2Since the first laser demonstrated that stimulated emission processes in an optical medium can implement a powerful, coherent light source 1 , the field of photonics has witnessed an explosion of applications in telecommunications, lighting, displays, medicine, and optical physics amongst others. Integration of photonic and electronic devices to leverage the advantages of both has subsequently attracted great interest. In particular, integration of optical interconnects onto silicon (Si) chips has become critical as ongoing miniaturization of Si logic elements has incurred a bottleneck in inter-and intra-chip communications 2,3 . Efforts towards creating on-chip light sources for optical interconnects have included engineering silicon and germanium for optical gain 4-6 and stimulated Raman scattering 7-9 . Concurrently, III-V lasers have been heterogeneously bonded onto silicon substrates [10][11][12] . However, numerous challenges face these approaches. Wafer bonding have low yields because of a stringent surface flatness requirement down to the atomic scale, while group IV emitters must overcome an indirect band gap that offers exceedingly inefficient radiation. Monolithic growth of high-performance III-V lasers on silicon thereby remains a "holy grail" for cost-effective, massively scalable, and streamlined fabrication of on-chip light sources.The fundamental roadblock facing monolithic integration up to now has been a large mismatch of lattice constants and thermal expansion coefficients between III-V materials and The nanopillar-based laser is schematically depicted in Figure 1A. shows the hexagonal cross-section of the nanopillar, which results from its unique single crystal wurtzite structure 15 . As we will later show, the as-grown nanopillar structure provides a natural optical cavity supporting unique resonances that have not been observed before to the best of our knowledge. As such, nanopillars do not require additional top-down processing to form on-chip optical cavities. Instead, they provide a viable bottom-up approach towards integrating light sources and resonators onto a silicon chip.Importantly, nanopillars possess several critical advantages for optoelectronic integration onto silicon. They grow at a low temperature of 400 °C, which is dra...

Single Crystalline InGaAs Nanopillar Grown on Polysilicon with Dimensions beyond the Substrate Grain Size Limit

“…Other growth parameters are similar to those used for growth on silicon substrate in our previous work. 10 Hexagonal shape is well preserved. As the density is very high, some of the pillars cross each other during the growth.…”

“…Lasing is attributed to a helically propagating mode in which light spirals along the well-faceted hexagonal nanopillar. 10 Although there is a detuning between gain and cavity mode, a 13dB side-mode suppression ratio is observed at 1.5 times threshold pump power (P th ). Figure 6(b) shows the output power and spectra linewidth as a function of pump power.…”

Lasing in direct-bandgap GeSn alloy grown on Si

“…In order to overcome this drawback, several routes have been followed, such as the all-optical Si Raman laser 2 or the heterogeneous integration of direct bandgap III-V lasers on Si [3][4][5][6][7] . Here, we report on lasing in a direct bandgap group IV system created by alloying Ge with Sn 8 without mechanically introducing strain 9,10 .…”

Transfer printing of semiconductor nanowire lasers

“…Semiconductor NWs are expected to be a key component across numerous applications, and one of the most investigated is their use as nanoscale laser sources (see [1][2][3][4][ [22][23][24][25][26][27][28][29] and references therein). Since the report of the first NW lasers over 15 years ago [4], research progress has been phenomenal, and NW lasers built from different materials, e.g.…”

“…Since the report of the first NW lasers over 15 years ago [4], research progress has been phenomenal, and NW lasers built from different materials, e.g. Group III-nitrides [22][23][24], Group II-VI [25], Group III-V [26][27][28], perovskites [29][30][31], and with operating wavelengths extending from the ultraviolet to the infrared have been demonstrated. The properties of NW lasers such as their highly localised emission and extremely reduced foot-print ensure that they will be key coherent light sources for nanophotonics-enabling technologies, e.g.…”