Abstract: The n-p junction short-wavelength and mid-wavelength Hg_1-xCd_xTe photovoltaic detectors have been fabricated using proton irradiation to create the n-type layer, with the cut-off wavelength range 1.6~7.0μm. The blackbody detectivity at 6.75μm was 2.3 × 10¹⁰ cmHz^1/2W^-1, the quantum efficiency at the peak was 28%, and the R₀A product was 157Ω·cm². It is obtained to be an abrupt junction through capacitance-voltage characteristic measurements . The noise frequency spectra show that 1/f noise in low frequency (< 300Hz) and thermal noise in middle and high frequency is mainly concerned. At the same time the changes of cut-off wavelength between materials and devices before and after irradiation were also explained. For short wavelength photodiode it can sustain up to 15V reverse voltage at room temperature.