The structural, electronic, and optical properties of amorphous InSb and InAs0.3Sb0.7 films deposited on Corning glass, Al2O3 CdZnTe, SiO2-Si, and CaF2 substrates by Radio Frequency (RF) magnetron sputtering have been studied as they relate to Mid and Long Wavelength Infrared (MWIR and LWIR) detection. Depositions at elevated substrate temperature and pressure of <10 mTorr Ar showed an emergence of crystalline grains with strong X-ray diffraction peaks at the (111) and (220) orientations. Electronically, the amorphous InSb and InAs0.3Sb0.7 films deposited at 300 K show hopping conduction with resistance in InSb ranging from 44 to 1.1E8 Ω-cm at 300 K and 84 K, respectively. Optical analysis using Fourier transform infrared spectroscopy (FTIR) shows the absorption of these films has an absorption tail, which shows the differing activation energies in InSb and InAs0.3Sb0.7. Amorphous InSb and InAs0.3Sb0.7 films showed responsivity in excess of 100 V/W for 6 μm thick films held at 233 K.