Influence of hydrogen impurity on the resistivity of low temperature grown p-AlxGa1-xN layer (0.08 ≤ x ≤ 0.104)
Low temperature grown p-AlGaN layer with a small resistivity is crucial to improve the performance of the GaN-based laser diodes (LDs). In this study, growth temperature of the p-AlxGa1-xN (0.08 ≤ x ≤ 0.104) layers are controlled to be relatively low, and the influence of hydrogen impurity on the resistivity is investigated in detail. According to the dependence of hole concentration and resistivity on hydrogen impurity concentration, it is found that when Mg doping concentration is unchanged, reducing hydrogen impurity concentration in p-AlxGa1-xN (0.08 ≤ x ≤ 0.104) layers could reduce the resistivity effectively, which is attributed to weaken the compensation or passivation effect of hydrogen impurities on Mg acceptors. A p-Al0.09Ga0.91N layer with a low resistivity of 4.6 Ω cm has been achieved.