Effect of the growth temperature on the formation of deep-level defects and optical properties of epitaxial BGaN

The electrical, optical, and high-resolution photoinduced transient spectroscopy (HRPITS) measurements are used for the characterization of boron gallium nitride (BGaN) epitaxial layers (containing about 1% of B) grown by MOCVD in the temperature range of 840–1090 °C. It is argued that the main influence on the changes in the electrical properties of BGaN layers is caused by the generation of interstitial boron ( B i ) that accumulates at the grain boundaries regions as well as out diffuses toward the layers surface. The HRPITS measurements show that the growth temperature also has a significant influence on the concentrations of deep-level defects formed within the BGaN grains. The photoluminescence measurements revealed a band at 2 eV. The determined by HRPITS trap energies give a base for the explanation of characteristics for the BGaN broad luminescence band around 2 eV. It is highlighted that such defects as interstitial B i + and gallium vacancies ( V Ga ) are mobile and can be essential for understanding the electrical and optical properties of BGaN epitaxial layers. Graphical abstract