NHEQuanLEA - Hybrid graphene/III-V system selectively grown on Si nanotips: A correlation study of structural and optoelectronic properties
Monolithic growth of group III-V compound semiconductors with their superior optoelectronic properties on silicon (Si) is a sophisticated solution for the integration of III-V devices into mature Si technology and CMOS platforms. In spite of large efforts for the III-V/Si epitaxy over the last decades, the growth of high quality, low-defect density III-V materials on Si remains still a challenge due to heterogeneous material properties, such as lattice spacing, symmetries of the crystals, surface energy, and thermal-expansion coefficients.
Our project NHEQuanLEA investigates the use of the nanoheteroepitaxy (NHE) method for monolithic growth of III-V quantum structures on patterned Si wafers. This approach reduces plastic relaxation via dividing the strain energy between the III-V layer and the underlying Si structures, allowing better control of the III-V quantum structures position, suppressing contamination segregation and achieving lower defect densities in the III-V material. In order to have a broad range for tailoring the strain and the optoelectronic properties of III-V material, we focus on growing GaxIn1-xP buffer layers on Si nanotips and to use strain-engineered quantum wells/dots embedded in the buffer layer as active electron-hole recombination channels.
Graphene (Gr) will be later utilized as electrical top contact, which shell be beneficial for the device performance due to its high optical transparency and electrical transport qualities. The structural properties of Gr after transfer onto the III-V/Si and, particularly, the defects at the Gr/III-V interface as well as the charge transfer are parts of this study.
Our efforts will be accompanied by research for precise material control using combined growth techniques, and correlated structural and optoelectronic characterization on ensembles of quantum light emitters as well as on single III-V nano islands.
Our project aims to pave the way for future development of efficient and tunable III-V light emitters on the Si platform for integrated optoelectronics.
This project is funded by the DFG under grant agreement No 428250328 (NHEQuanLEA).
- Humboldt-Universität zu Berlin
- Xi'an Jiaotong University