E-Band InAs Quantum Dot Micro-Disk Laser with Metamorphic InGaAs Layers Grown on GaAs/Si (001) Substrate

Abstract

The direct growth of III-V quantum dot (QD) lasers on silicon substrate has been rapidly developing over the past decade and has been recognized as a promising method for achieving on-chip light sources in photonic integrated circuits (PICs). Up to date, O- and C/L-bands InAs QD lasers on Si have been extensively investigated, but as an extended telecommunication wavelength, the E-band QD lasers directly grown on Si substrates are not available yet. Here, we demonstrate the first E-band (1365 nm) InAs QD micro-disk lasers epitaxially grown on Si (001) substrates by using a III-V/IV hybrid dual-chamber molecular beam epitaxy (MBE) system. The micro-disk laser device on Si was characterized with an optical threshold power of 0.424 mW and quality factor (Q) of 1727.2 at 200 K. The results presented here indicate a path to on-chip silicon photonic telecom-transmitters.

Keywords: E-band quantum dots; III-V on silicon; micro-disk lasers; molecular beam epitaxy; photonic integrated circuits.

Figure 1

Schematic diagram of the E-band InAs QD micro-disk laser sample epitaxially grown on GaAs/Si (001) template with a 7-layer InAs/InGaAs QDs as active region. The right diagram shows the detailed structure of InGaAs metamorphic buffer layer grown by step-graded method.

Figure 2

(a) Bright-field cross-sectional TEM image of a five-layer of E-band InAs/InGaAs QDs grown on InGaAs/GaAs/Si substrate. (b,c) show the zoomed-in TEM images at the InGaAs/GaAs interface and InAs QD active region, respectively.

Figure 3

Diameter and height histograms of the surface InAs/InGaAs QDs on (a) GaAs (001) substrate and (b) GaAs/Si (001) substrate, respectively. Insets in (a,b) show the $1\times 1{\mathsf{\mu }\mathrm{m}}^2$ AFM images of the surface InAs/InGaAs QDs on these two substrates.

Figure 4

(a) Room-temperature PL spectra of InAs/InGaAs QDs on GaAs (001) and GaAs/Si (001) substrates, respectively. Inset: the cross-sectional TEM image of a buried InAs/InGaAs QD on InGaAs/GaAs/Si (001) substrate. (b) Arrhenius plots of temperature-dependent IPLI of the InAs QDs on GaAs and Si, respectively.

Figure 5

(a) Schematic diagram of an E-band micro-disk laser on GaAs/Si (001) substrate with seven layers of InAs/InGaAs QDs as active region and 600 nm InGaAlAs sacrificial layer. (b) SEM image of a fabricated micro-disk laser on Si with a diameter of 4 μm.

Figure 6

(a) The output intensity of the micro-disk laser on Si substrate versus the effective pumping power (L-L curve). Inset: the log-log scale plot of the non-linear L-L curve. (b) Pumping-power-dependent lasing spectra of the laser device. Inset: zoomed-in spectra collected at the pumping power below and above threshold.

Figure 7

(a) Zoomed-in spectra of the micro-disk laser on the Si substrate at the increasing pumping power, indicating multi-peak lasing property. (b) The relationship of the two lasing peak wavelengths as a function of the pumping power. Inset: zoomed-in spectrum of the dominant peak (1364.5 nm) from the laser fitting by Lorentzian curve at 1.1 × P_th, showing a 0.79 nm linewidth.