Structural and Electrical Properties of [(Co_1-xCu_x)_0.2(Ni_0.3Mn_0.7)_0.8]₃O₄Spinel Thin Films for Infrared Sensor Application

Abstract

Co1-xCux)0.2(Ni0.3Mn0.7)0.8]3O4 (0≤x≤1) thin films prepared by metal organic decomposition process were fabricated on SiN/Si substrate for infrared sensor application. Their structural and electrical properties were investigated with variation of Cu dopant. The [(Co1-xCux)0.2(Ni0.3Mn0.7)0.8]3O4 (CCNMO) film annealed at 500℃ exhibited a dense microstructure and a homogeneous crystal structure with a cubic spinel phase. Their crystallinity was further enhanced with increasing doped Cu amount. The 120 nm-thick CCNMO (x=0.6) thin film had a low resistivity of 53 Ω•cm at room temperature while the Co-free film (x=1) showed a significantly decreased resistivity of 5.9 Ω•cm. Furthermore, the negative temperature coefficient of resistance (NTCR) characteristics were lower than -2%/℃ for all the specimens with x≥0.6. These results imply that the CCNMO (x≥0.6) thin films are a good candidate material for infrared sensor application.