Growth of thin AlInN∕GaInN quantum wells for applications to high-speed intersubband devices at telecommunication wavelengths

In this article, we report on growth of AlInN∕GaInN multi-quantum-wells (MQWs) with high Al content (93%) by rf-plasma-assisted molecular-beam epitaxy on (0001) GaN/sapphire templates and on bulk GaN crystals. A series of samples with a barrier thickness of 3nm and with different well thicknesses of 1.5–3nm was grown. The wells were doped with Si at a concentration of 5×1019cm−3. Structures grown on (0001) GaN-based substrates are crack-free, as demonstrated by Nomarski contrast and scanning electron microscopy measurements. X-ray diffraction mapping of a and c lattice parameters shows that AlInN∕GaInN MQWs are fully strained and have up to 7% indium in the barriers and up to 10% In in the quantum wells. These structures exhibit intersubband absorptions at room temperature at a wavelength in the range of 2.45–1.52μm. The AlInN∕GaInN strain-compensated MQW structures, having good quality, are very attractive for ultrahigh-bit-rate telecommunication applications at 1.55μm wavelengths. In addition, because o...