No abstract

No abstract

Thermodynamic analysis and experimental demonstration of β-Ga2O3 growth by metalorganic vapor phase epitaxy using triethylgallium (TEG) and oxygen (O2) precursors were performed. Thermodynamic analysis revealed that the O2 supplied is preferentially used for the combustion of hydrocarbons and H2 derived from TEG. Therefore, the use of high growth temperatures and high input VI/III ratios is essential for the complete combustion of hydrocarbons and H2, and β-Ga2O3 growth. The use of an inert gas as the carrier gas was also determined as necessary to grow β-Ga2O3 at high temperatures. Based on these results, a ( 2 ¯ 01) oriented smooth β-Ga2O3 layer could be grown on a c-plane sapphire substrate at 900 °C with a growth rate of 1.4 μm h−1 at an input VI/III ratio of 100. The grown layer showed a clear optical bandgap of 4.84 eV, and impurity concentrations of hydrogen and carbon were below the background levels of the measurement system.

We investigated the performance of InGaN/GaN light-emitting diodes (LEDs) fabricated using NH3 with intentionally added H2O. The H2O concentrations in NH3 were assessed quantitatively using an optical analyzing system. The oxygen concentration in the active layer was measured by secondary ion mass spectrometry and observed to increase with increasing H2O concentration. In addition, the oxygen was predominantly incorporated in InGaN well layers rather than in GaN barrier layers. The performance of LEDs markedly deteriorated with increasing H2O concentration. It was found by current–voltage measurement that oxygen in the multi quantum well layer increases leakage current.

No abstract