Effect of small flow hydrogen treatment at the upper well/barrier interface on the properties of InGaN/GaN multiple quantum wells. (July 2017) - Zhu, Yadan
Abstract: To enhance the quality of InGaN/GaN multiple quantum wells (MQWs), a small hydrogen flow is introduced to treat the upper well/barrier interface. High-resolution X-ray diffraction results indicate that hydrogen treatment improves the interface quality of MQWs. Room temperature photoluminescence (PL) tests show that integrated PL intensity is enhanced by 57.6% and line width is narrowed, while emission peak energy is almost unchanged. On the basis of temperature-dependent PL characteristics analysis, it is concluded that hydrogen treatment decreases non-radiative recombination centers in active region, yet has little impact on carrier localization. Moreover, surface roughness and V-pit density are significantly reduced after hydrogen treatment as revealed by atomic force microscopy. Because the emission energy is quite stable after the hydrogen treatment, this method can also be promoted to improve the quality of green and yellow-green emission MQWs. Highlights: Small flow hydrogen treatment is conducted at the upper well/barrier interface to improve the quality of active region. Surface and interface properties are improved when hydrogen treatment is adopted. Room temperature photoluminescence intensity is significantly enhanced after hydrogen treatment. The enhancement in optical quality originates from the decreased defect density, rather than carrier localization.