Conductive isostructural compounds

Abstract

A family of isostructural compounds have been prepared having the general formula A_nPb_mBi_nO_2n+m. These compounds possess a NaCl lattice type structure as well as low thermal conductivity and controlled electrical conductivity. Furthermore, the electrical properties can be controlled by varying the values for n and m. These isostructural compounds can be used for semiconductor applications such as detectors, lasers and photovoltaic cells. These compounds also have enhanced thermoelectric properties making them excellent semiconductor materials for fabrication of thermoelectric devices.

Description

[0001]This is a regular application of provisional application Ser. No. 60 / 103,961 filed Oct. 13, 1998.SPONSORSHIP[0002]Work on this invention was sponsored in part by the Office of Naval Research, Grants N00014-94-1-0935 and N00014-98-1-0443 and Defense Advanced Research Projects Agency Grant DAAG55-97-1-0184. The Government may have certain rights to the invention.FIELD OF THE INVENTION[0003]This invention relates generally to new compounds exhibiting crystal lattice morphologies and, more particularly, to conductive compounds having NaCl-type cubic crystal lattice structures.BACKGROUND OF THE INVENTION[0004]Semiconductor materials are at the core of current technological infrastructure and continuing advancements. Various semiconductors enable many technologies. For example, Si and Ge enable high speed computing, GaAs, InSb and their derivatives enable optoelectronics and communication devices, Si and GaAs are the vital components of solar energy converters, GaN and GaAs alloys e...

AI Technical Summary

Benefits of technology

[0011]The present invention relates to new isostructural compounds having the general formula AnMmM′nO2n+m where A is an alkali metal, such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), or cesium (Cs) or the transition metal silver (Ag) or thallium (TI) and mixtures thereof, M is lead (Pb), tin (Sn), germanium (Ge), calcium (Ca), strontium (Sr), barium (Ba), any divalent transition metal or mixtures thereof, M′ is bismuth (Bi), antimony (Sb) or mixtures thereof, and Q is sulfur (S), selenium (Se), or tellurium (Te) and mixtures thereof. These compounds possess an NaCl-type cubic lattice crystal structure where A, M and M′ occupy the Na sites and Q occupies the Cl (chlorine) sites. This family of compounds combine isotropic morphology, an advantageous property for device processing, with low thermal conductivity and widely ranged electrical conductivity. Further, certain properties such as the electrical properties of the compounds can be controlled by varying the values for n and m. The isostructural compounds of the present invention are therefore good candidates for semiconductor applications in thermoelectronic devices, detectors, and photovoltaic cells, by way of non-limiting example.

Problems solved by technology

Many current semiconductor materials are limited in that they do not allow for fine adjustment of the band gap.

Furthermore, some semiconductor materials contain volatile elements causing changes in the composition of the materials and consequently unwanted changes in the band gap.

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