The Use of Cathodoluminescence during Molecular Beam Epitaxy Growth of Gallium Nitride to Determine Substrate Temperature

In-situ cathodoluminescence (CL) measurement during growth of gallium nitride (GaN) by molecular beam epitaxy (MBE) was investigated for determining substrate temperature. Cathodoluminescence was easily observed from room temperature up to and beyond typical temperatures used during growth. Determination of the peak energy of the CL spectrum allows unambiguous determination of the substrate temperature. Temperature drift and reproducibility issues during growth of GaN were observed using the in-situ CL measurement.