We have investigated the growth of InAs/GaSb type-II superlattices by gas-source molecular-beam epitaxy, where Sb cracker cell and AH(3) high-temperature injector are used to provide Sb and As flux, respectively. Sharp InAs/GaSb interfaces can be obtained at optimized growth conditions, revealed by high-resolution transmission electron microscopy. Moreover, it was found that the intrinsic net tensile strain of the InAs/GaSb superlattices can be partially compensated by intentional insertion of a sub-monolayer InSb layer at the interfaces of InAs and GaSb. Finally, based on InAs/GaSb superlattices grown by gas-source molecular-beam epitaxy (GSMBE), we have fabricated a photodiode with cut-off wavelength of 4.9 mu m. (C) 2008 Elsevier B.V. All rights reserved.