Room temperature deposited vanadium oxide thin films for uncooled infrared detectors

We demonstrate the room temperature deposition of vanadium oxide thin films by pulsed laser deposition (PLD) technique for application as the thermal sensing layer in uncooled infrared (IR) detectors. The films exhibit temperature coefficient of resistance (TCR) of 2.8%/K implies promising application in uncooled IR detectors. A 2-D array of 10-element test microbolometer is fabricated without thermal isolation structure. The IR response of the microbolometer is measured in the spectral range 8-13 mum. The detectivity and the responsivity are determined as similar to6 x 10(5) cm Hz(1/2)/W and 36 V/W, respectively, at 10 Hz of the chopper frequency with 50 muA bias current for a thermal conductance G similar to 10-3 W/K between the thermal sensing layer and the substrate. By extrapolating with the data of a typical thermally isolated microbolometer (G similar to 10(-7) W/K), the projected responsivity is found to be around 10(4) V/W, which well compares with the reported values. (C) 2003 Elsevier Science Ltd. All rights reserved.