AFM Observation of GaN Grown on Different Substrates at Low Temperatures

Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion The analysis shows that no apparent relationship exists between the optical properties and layer morphology.