Regulation of surface kinetics: rapid growth of n-AlGaN with high conductivity for deep-ultraviolet light emitters†
A rapid growth strategy for n-AlGaN with fine electrical properties has been put forward aiming at deep-ultraviolet light emitters. By shortening the terrace width using sapphire with large miscut angles, a growth window allowing a higher rate as well as a lower temperature is realized for Al-rich AlGaN, which is beneficial for the control of surface morphology and compensation defects in n-AlGaN. Specifically, a rate of 2.3 μm h−1 for n-Al0.55Ga0.45N is achieved at 1050 °C on sapphire with a miscut angle of 0.5°, where the typical step-terrace morphology demonstrates the step-flow growth of n-Al0.55Ga0.45N. In addition, impressive electrical properties of n-Al0.55Ga0.45N are obtained at the appropriate low growth temperature (1050 °C), with the electron concentration and conductivity being 1.34 × 1019 cm−3 and 102.8 S cm−1, respectively. As such, a 280 nm deep-ultraviolet light-emitting diode structure, containing 1.5 μm-thick n-Al0.55Ga0.45N, is accomplished within 3.5 h, which meanwhile exhibits an obvious reduction of the operating voltage in the flip-chip configuration of devices.