Development Of Transparent Lsco and Lscno Conductors for Optical Shutter Systems

Abstract

We have prepared lanthanum strontium cobalt oxide (La0.50Sr0.50CoO3; LSCO 50/50) and lanthanum strontium cobalt nickel oxide (La0.50Sr0.50Co0.50Ni0.50O3; LSCNO) as candidate transparent electrodes for use in a shutter-based infrared sensor protection device. The shutter device requires that the electrode be transparent (80% transmission) and have moderate sheet resistance (300 ω/sq.). Because of the effects of film thickness on intrinsic material properties, such as resistivity and extinction coefficient, and simple engineering issues (i.e., the relationship between film thickness, resistance and transmission), films of various thicknesses were prepared to achieve an optimal balance of electrical and optical performance. van der Pauw measurements and FTIR spectroscopy were used to study thin film properties. The best LSCO films prepared demonstrated electrical (438 ω/sq.) and optical (68% transmission at 8 µm) properties that did not meet the target property goals for this application. However, the LSCNO films (of optimal thickness) offered performance (323 µ/sq. and 73% transmission) close to the device requirements.

Chopping of near- and mid-infrared radiation using a curled electrostatic MEMS actuator

“…A number of conducting oxide materials are being developed with transparency in the far IR for use as the IR transparent electrode. [13][14][15] Fabrication runs are currently in progress using sapphire substrates and NiRh 2 O 4 fixed electrodes for use in mid-IR applications. A discussion of IR transparent electrodes is presented in a later section.…”

“…16 First, the transmission of ITO is limited to the near IR, and this falls to 35% at 2 µm and to 5% at 2.7 µm. [13][14][15] In particular, we have been investigating Ni-based spinel thin films including NiCo 2 O 4 and NiRh 2 O 4 for the fixed electrode material. These materials with p-type conductivity provide high transmission in the IR range as shown in Figure 7.…”