Characterization of AlGaInN layers using X‐ray diffraction and fluorescence

Abstract

Quantum well structures for nitride-based LEDs are mainly grown in c-direction, whereby the quantum confined Starkeffect (QCSE) reduces the overlap of the electron and hole wave function and with it the internal quantum efficiency. The reason for that is the difference in polarization of the quantum well and barrier materials. In order to balance these polarizations, quaternary (AlGaIn)N layers for the later use as barrier material have been grown. In addition to the bandgap energy, another parameter, the polarization, can be controlled in this way. As a standard characterization method X-ray diffraction measurements have been performed. Due to the impossibility of fully determining the composition using this method, total reflection X-ray-fluorescence (TXRF) has been used to get the missing information.

Polarization engineering of c‐plane InGaN quantum wells by pulsed‐flow growth of AlInGaN barriers

“…As shown in Fig. 1 (a), the content of AlN in the solid composition of pulsed AlGaN calibration samples stays almost constant over the temperature range from 690 to 800 8C in accordance with observations by other authors [22,23]. The small change is negligible as compared to the change of the In-amount in InGaN and AlInN layers.…”

“…The same calibration was described in Ref. for continuously grown ternary alloys. The growth temperature dependence of composition and growth rate for the ternary layers are depicted in Fig.…”