Characterization and Optimization of Hg sub 1-x Cd sub x Te Infrared Detector Materials.
Abstract
The objective of this contract was to characterize the ternary compound Hg(1-x)Cd(x)Te. Emphasis was primarily placed on the 0.1 eV composition because of its utility as an intrinsic infrared photoconductor. A distinct advantage of these materials as a photoconductor operating at the longer wavelengths is their high absorption coefficient which allows operation at higher temperatures and also thinner samples. It has been well established that (HgCd)Te can be fabricated with the necessary composition to yield suitable detectors with the desired wavelength response and meeting the basic criteria for intrinsic photoconductors. However, as in the development of any solid state system, the metallurgical surfaces can degrade performance. In the case of (HgCd)Te detectors, the various surface treatments used during fabrication can greatly influence detector performance by changing the electrical and photoconductive properties. For example, treatment wity H2O2 is known to accumulate the surface; whereas, methonalbromine depletes the surface of electrons. Since the noise voltage is greater for a depleted surface than for an accumulated surface, it appears than an accumulated surface is more desirable for photoconductors. In order to better understand the surface and its influence on the bulk properties, the technical effort in this program was divided into three parts: (1) measurement of bulk transport properties utilizing galvano-thermomagnetic measurements; (2) determination of surface state distributions from capacitance-voltage (C-V) and capacitive derivative-voltage (C-V) measurements on metal-insulator-semiconductor (MIS) structures, and (3) low frequency (l/f) noise measurement.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1976
- Accession Number
- ADA023958
Entities
People
- William F. Leonard
Organizations
- Southern Methodist University