λ～ 1.49-3.4 μm intersubband absorptions in (CdS/ZnSe)/BeTe quantum wells grown by molecular beam epitaxy

摘要

We demonstrate that intersubband transition (ISBT) can be tuned in a wide range (far to near infrared) in (CdS/ZnSe)/BeTe quantum wells (QWs). The strain in the structures shifts from compressive to tensile due to formation of Be-Se and Zn-S bonds at interfacial region, which significantly affects the ISBT performance. ISBTs of λ= 1.52-3.4 μm with narrow linewidths (67-92 meV) are observed in QWs with the nominal well width of 3.75-14 molecular layers (MLs). ISBT at 1.49 μm was also observed in QWs with 3.5 ML well width by means of photoinduced absorption measurement, indicating carrier compensation limits the shortest ISBT wavelength.