GaAs-based nanowire heterostructure for light generation in the telecommunication O band on Si

20.05.2020

The monolithic integration of light emitters on Si remains an important technological challenge for the development of intra-chip optical connections, as well as inter-chip connections. In this context, GaAs nanowires grown on Si substrates offer great potential, but their effective use for Si photonics technologies requires operation in the Si transparent window, with special relevance of the telecommunication bands for potential data transfer applications. Here, we present a novel coaxial nanowire heterostructure to extend the emission range of GaAs-based nanowire devices into the telecommunication O band.

Our key idea is to combine the nanowire geometry for integration on Si substrates with the formation of InAs quantum dots on the nanowire sidewalls to reach longer emission wavelengths. Following concepts for planar heterostructures, we embed the quantum dot layer in a coaxial In_0.15Ga_0.85As shell grown around the GaAs nanowire core. This step enhances the wavelength extension and leads to a coaxial GaAs/(In,Ga)As dot-in-a-well (DWELL) nanowire heterostructure.  In order to trigger quantum dot formation on the {110} nanowire sidewalls—surfaces on which otherwise InAs quantum dots do not form—we employ Bi as a surfactant. The photoluminescence of our DWELL nanowires peaks at a wavelength of 1.27 µm at room temperature, thus reaching the telecommunication O band. This extension of the emission range is caused by the thermal escape of charge carriers from small quantum dots and the recapture in larger quantum dots. Finally, we have fabricated light-emitting diodes (LEDs) from ensembles of DWELL nanowires with a radial p–i–n junction. These LEDs exhibit room temperature operation with a peak electroluminescence wavelength of 1.26 µm, which constitutes the longest wavelength of electroluminescence demonstrated for GaAs-based nanowires.  These results illustrate the potential of heterostructures combining quantum dots and the nanowire geometry and push the electroluminescence from GaAs-based nanowires into the spectral region relevant for integrated optical interconnectors and data communication, opening up new perspectives for Si photonics integration.

Author: J. Herranz , P. Corfdir , E. Luna , U. Jahn , R. B. Lewis , L. Schrottke , J. Lähnemann , A. Tahraoui , A. Trampert , O. Brandt , L. Geelhaar
Title: Coaxial GaAs/(In,Ga)As dot-in-a-well nanowire heterostructures for electrically driven infrared light generation on Si in the telecommunication O band
Source: ACS Appl. Nano Mater. , 3 , 165 ( 2020 )
DOI: 10.1021/acsanm.9b01866