Dislocation-Free InxGa1-xP1-yNy/GaP1-zNz Double-Heterostructure Light Emitting Diode on Si Substrate

An In x Ga1-x P1-y N y /GaP0.982N0.018 double-heterostructure (DH) light-emitting diode (LED) was fabricated on a Si substrate using solid-source molecular beam epitaxy (SS-MBE) with an rf plasma nitrogen source. It was confirmed by high resolution X-ray diffraction (XRD) analysis that the structure of the LED had a small lattice mismatch to the Si substrate. A cross-sectional image obtained by transmission electron microscopy (TEM) revealed that there were no threading dislocations in the epitaxial layers. The electroluminescence (EL) properties were also evaluated. The EL peak wavelength of an In x Ga1-x P1-y N y /GaP0.982N0.018 DH LED was 665 nm at room temperature when the indium (x) and nitrogen contents (y) were 4.0% and 3.8%, respectively. A relatively wide EL spectrum was obtained. These specific features of EL spectra could be attributed to a long band tail formed by nitrogen in the In x Ga1-x P1-y N y active layer.