Hydrogen induced quality improvement of GaNAs layers grown by chemical beam epitaxy

•GaNAs layers are grown with and without hydrogen by chemical beam epitaxy.•Both XRD and AFM results show that hydrogen improves the quality of GaNAs layer.•Hydrogen induced two-dimensional growth mode is responsible for the improvement.•This conclusion is also supported by XRD and PL results for InGaNAs/GaAs SQWs. In order to investigate the impact of hydrogen on the quality of GaNAs, GaNAs layers are grown by chemical beam epitaxy (CBE) with and without hydrogen. X-ray diffraction (XRD) results show that hydrogen improves nitrogen incorporation significantly for GaNAs. For GaNAs layer grown without hydrogen, nitrogen incorporation cannot be detected, whereas for GaNAs layer grown with hydrogen, nitrogen incorporation can be clearly detected by XRD. Atomic force microscopy (AFM) observations show that root mean square (RMS) roughness for GaNAs layer grown without hydrogen is around 34 times higher than that grown with hydrogen. High quality GaNAs layer with RMS roughness of around 1 monolayer is successfully obtained with hydrogen. Based upon XRD and AFM results, it is suggested that atomic hydrogen induced enhancement of two-dimensional growth mode is responsible for the quality improvement. This conclusion is also supported by XRD and photoluminescence (PL) results for InGaNAs/GaAs SQWs grown with and without hydrogen.