Disclosed is a low temperature method of fabrication of short-wave infrared (SWIR) detector arrays (FPA) including a readout wafer and absorption layer connected for improved performances. The absorber layer includes a SWIR conversion layer with a GeSn or SiGeSn alloy. A first series of process steps realizes a CMOS processed readout wafer. A buffer layer is transferred on the readout wafer and annealed at temperatures compatible with the CMOS substrate, achieving a high quality crystalline buffer layer. The method assures a temperature profile between the light entrance surface of the buffer layer, and the readout electronics so the annealing temperature remains compatible with the CMOS. The buffer layer is used for further growth of a GeSn or SiGeSn structure to create the conversion layer and achieve the final structure of the SWIR FPA. Also disclosed is a SWIR FPA detector as realized by such method, and SWIR FPA applications.