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

Polarization‐field reduction in c‐plane InGaN multi‐quantum well (MQW) structures is achieved by pulsed‐flow growth of quaternary AlInGaN barriers using metalorganic vapor phase epitaxy (MOVPE). The pulsed‐flow growth allows for precise control of the quaternary composition at very low growth rate. In photoluminescence (PL) experiments a blue‐shift of the MQW emission wavelength is observed by successive adjustment of the AlInGaN barriers toward reduced polarization mismatch to the InGaN quantum wells. Accordingly, we find a decreasing radiative lifetime by time resolved cathodoluminescence (TRCL). The application of AlInGaN as barrier material instead of conventional GaN is limited by plastic relaxation. While for InGaN‐QWs emitting in the violet‐blue spectral region, fully polarization‐matched AlInGaN barriers can be realized, for long‐wavelength (green spectral region) severe lattice relaxation is observed leading to inferior optical properties as compared to binary GaN barriers.