RF sputtered Hg¿-XCdXTe infrared detectors
Thielsch, Donald Kurt
Wilson, William L.
Master of Science
Thin films have been prepared by RF sputtering from an inhomogeneous HggCdg 2Te target onto glass substrates. Both mercury and argon were used as sputter gases. Each film consisted of a Hall bar and a 2-element detector array. Electron microprobe analysis showed the existence of a lateral composition gradient. Electrical measurements provided resistivity, mobility, and carrier concentration information. The carrier concentration was found to vary with sputter deposition rate. The detectors exhibited both photoconductive and photovoltaic response. The photovoltage was believed to have been due to a graded band gap, induced by the composition gradient. Spectral response ranged from less than 4 microns to more than 14 microns. Best photoconductive D (5, 275) was 5.5 x 17 cm Hz1/2 W-1 and best photovoltaic D (5°, 275) was 1.22 x 17 cm Hz1/2 W-1 for detectors cooled to 125° K.