<title>Photovoltaic HgCdTe detectors for advanced GOES instruments</title>

Abstract

There has been significant progress made during the past several years in PV HgCdTe technology for advanced long wavelength remote sensing applications. Useful cutoff wavelengths have been extended to beyond 17.0 jim. Junction quality has been improved to the point that D* > 3x1011 cm4Hz/W can be achieved at temperatures of 60-65 K. The Atmospheric Infrared Sounder (AIRS) instrument, scheduled for launch in the year 2000 as part of the NASA EOS Program, uses long linear multiplexed arrays of PV HgCdTe detectors with cutoff wavelengths extending as far as 15.0 .tm at 60 K. PV HgCdTe offers many advantages over PC HgCdTe for advanced remote sensing instruments: negligible 1/f noise, much higher impedance so that cold preamps or multiplexers are possible, backside-illuminated two-dimensional arrays of closely spaced elements, 1OX-100X better linearity, dc coupling for measuring the total incident photon flux, and a J2 higher BLIP D* limit. In this paper we compare the relative merits of PV and PC HgCdTe for advanced remote sensing instruments, we review recent data for linear arrays of PV HgCdTe with cutoff wavelengths as long as 17.5 tm at 70 K, and we project that PV HgCdTe should be able to meet or exceed the present demanding GOES LW Sounder D* requirements at T=100 K, with the additional benefits ofnegligible 1/fnoise and better linearity.