Quasi van der Waals Epitaxy of Single Crystalline GaN on Amorphous SiO₂/Si(100) for Monolithic Optoelectronic Integration

AbstractThe realization of high quality (0001) GaN on Si(100) is paramount importance for the monolithic integration of Si‐based integrated circuits and GaN‐enabled optoelectronic devices. Nevertheless, thorny issues including large thermal mismatch and distinct crystal symmetries typically bring about uncontrollable polycrystalline GaN formation with considerable surface roughness on standard Si(100). Here a breakthrough of high‐quality single‐crystalline GaN film on polycrystalline SiO2/Si(100) is presented by quasi van der Waals epitaxy and fabricate the monolithically integrated photonic chips. The in‐plane orientation of epilayer is aligned throughout a slip and rotation of high density AlN nuclei due to weak interfacial forces, while the out‐of‐plane orientation of GaN can be guided by multi‐step growth on transfer‐free graphene. For the first time, the monolithic integration of light‐emitting diode (LED) and photodetector (PD) devices are accomplished on CMOS‐compatible SiO2/Si(100). Remarkably, the self‐powered PD affords a rapid response below 250 µs under adjacent LED radiation, demonstrating the responsivity and detectivity of 2.01 × 105 A/W and 4.64 × 1013 Jones, respectively. This work breaks a bottleneck of synthesizing large area single‐crystal GaN on Si(100), which is anticipated to motivate the disruptive developments in Si‐integrated optoelectronic devices.