The effect of barrier growth temperatures on blue InGaN (2 nm)/GaN (12 nm) multiple quantum wells was studied with samples grown by metallorganic chemical vapour deposition. It was found that InGaN active layers composed of InGaN quasi-dots of 2 ± 0.2 nm in diameter, changing from their homogeneous nature, could be obtained by elevating the barrier growth temperature from 700 to 800°C based on the results of energy-filtered high resolution transmission electron microscopy. These dots may have formed during the ramping process by in situ annealing. Strong piezoelectric field, 'S-shape-like' carrier transition and high internal quantum efficiency of 71.3% were observed in the sample with a higher barrier growth temperature closely related to the dot formation. Furthermore, the forward voltage and the light output power at 20 mA of light emitting diodes from the sample with dots were 0.3 V lower and 11% higher than that from the homogeneous multiple quantum wells.
All Science Journal Classification (ASJC) codes
- 化學 (全部)