Ultrafast intersubband electron relaxation at ∼1.55 μ wavelength in GaN/AlGaN quantum well structures

We report on the first comparative study of room temperature intersubband (IS) scattering lifetimes in a variety of single and coupled double GaN/AlGaN MQW samples at different excitation powers and wavelengths. Furthermore, samples with two types of QW barriers are compared: bulk-like barriers (85% AlN mole fraction) and superlattice (SL) barriers (65% AlN mole fraction). All samples were grown by molecular beam epitaxy on sapphire substrates.