Compositions of doped, co-doped and tri-doped semiconductor materials

Abstract

Semiconductor materials suitable for being used in radiation detectors are disclosed. A particular example of the semiconductor materials includes tellurium, cadmium, and zinc. Tellurium is in molar excess of cadmium and zinc. The example also includes aluminum having a concentration of about 10 to about 20,000 atomic parts per billion and erbium having a concentration of at least 10,000 atomic parts per billion.

I/we claim: 
     
         1 . A method for processing a semiconductor material, comprising:
 placing at least one element from Group II of the periodic table and at least one element from Group VI of the periodic table in a container;   mixing the at least one element from Group II and the at least one element from Group VI of the periodic table with a first dopant and a second dopant to form a mixture, wherein the first dopant includes at least one element from Group III or VII of the periodic table, and wherein the second dopant includes erbium at a concentration of about 10 to about 400,000 atomic parts per billion or dysprosium at a concentration of about 10 to about 10,000 atomic parts per billion; and   converting the mixture into a solid material.   
     
     
         2 . The method of  claim 1  wherein the first dopant includes aluminum at a concentration of about 10 to about 20,000 atomic parts per billion, and wherein the second dopant includes erbium. 
     
     
         3 . The method of  claim 1  wherein the first dopant includes indium at a concentration of about 10 to about 20,000 atomic parts per billion, and wherein the second dopant includes erbium. 
     
     
         4 . The method of  claim 1  wherein the at least one element from Group II of the periodic table includes cadmium, and wherein the at least one element from Group VI of the periodic table includes tellurium. 
     
     
         5 . The method of  claim 4  wherein the mixture further includes zinc, and wherein the mixture has a molar excess of tellurium over cadmium and zinc, the molar excess being between about 0.5% to about 75%. 
     
     
         6 . The method of  claim 1  wherein the first dopant includes chlorine at a concentration of about 10 to about 20,000 atomic parts per billion, and wherein the second dopant includes erbium. 
     
     
         7 . A method for preparing a co-doped semiconductor material having at least one element from Group II of the periodic table and at least one element from Group VI of the periodic table, wherein the method comprising:
 selecting a dopant from the group consisting of aluminum, chlorine, and indium;   selecting a co-dopant based on a formation energy of a complex between the at least one element from Group VI of the periodic table and the co-dopant; and   doping the semiconductor material with the selected dopant and the co-dopant.   
     
     
         8 . The method of  claim 7  wherein selecting a co-dopant element includes determining whether the co-dopant irreversibly combines with the at least one element from Group VI of the periodic table in a liquid phase. 
     
     
         9 . The method of  claim 7  wherein the at least one element from Group VI includes Tellurium, and wherein the co-dopant includes erbium. 
     
     
         10 . The method of  claim 7  wherein doping the semiconductor material includes doping the semiconductor material with the selected co-dopant at a concentration of about 10 to about 400,000 atomic parts per billion. 
     
     
         11 . The method of  claim 7 , further comprising decreasing intrinsic defects related to the at least one element from Group VI with the co-dopant. 
     
     
         12 . A method for forming a co-doped semiconductor material containing a first element from Group II of the periodic table and a second element from Group VI of the periodic table, the method comprising:
 selecting a first dopant from elements in Group III or Group VII of the periodic table based on a target resistivity of the semiconductor material;   determining a formation energy of a compound containing a rare earth metal and at least one of the first element and the second element; and   selecting the rare earth metal as a second dopant based on the determined formation energy and a target threshold of formation energy.   
     
     
         13 . The method of  claim 12  wherein determining the formation energy includes determining at least one of an enthalpy of formation and an entropy of formation of the compound containing the rare earth metal and at least one of the first element and the second element. 
     
     
         14 . The method of  claim 12  wherein if the formation energy is above the target threshold, selecting the rare earth metal as the second dopant. 
     
     
         15 . The method of  claim 12  wherein the determined formation energy corresponds to a heat of formation of the compound containing the rare earth metal and at least one of the first element and the second element, and wherein if the heat of formation is above the target threshold, selecting the rare earth metal as the second dopant. 
     
     
         16 . The method of  claim 12  wherein:
 the second element contains tellurium (Te); 
 the rare earth metal contains erbium (Er); and 
 determining the formation energy includes determining a formation energy of Er—Te complexes. 
 
     
     
         17 . The method of  claim 12  wherein:
 the second element contains tellurium (Te); 
 the rare earth metal contains erbium (Er); 
 determining the formation energy includes determining a formation energy of Er—Te complexes; 
 comparing the determined formation energy of Er-Te complexes to the target threshold; and 
 if the determined formation energy of Er-Te complexes is greater than the target threshold, selecting erbium (Er) as the second dopant. 
 
     
     
         18 . The method of  claim 12  wherein determining the formation energy includes determining if the rare earth metal combines with at least one of the first element and the second element irreversibly to form the compound in a liquid phase. 
     
     
         19 . The method of  claim 12  wherein determining the formation energy includes determining if a reaction product between the rare earth metal and at least one of the first element and the second element form stable solid domains in the bulk semiconductor material. 
     
     
         20 . The method of  claim 12 , further comprising selecting a concentration of the second dopant based on a target depletion characteristic of the semiconductor material. 
     
     
         21 . The method of  claim 20  wherein the target depletion characteristic includes a target charge carrier mobility and lifetime, and wherein selecting the concentration of the second dopant includes selecting a concentration of the second dopant based on the target charge carrier mobility and lifetime. 
     
     
         22 . The method of  claim 20  wherein the target depletion characteristic includes full depletion under a bias voltage, and wherein selecting the concentration of the second dopant includes selecting a concentration of the second dopant to achieve the full depletion under the bias voltage. 
     
     
         23 . The method of  claim 20  wherein the selected second dopant contains erbium (Er), and wherein selecting the concentration of the second dopant includes selecting a concentration of the second dopant to be about 10 to about 400,000 atomic parts per billion. 
     
     
         24 . A method for forming a co-doped semiconductor material, comprising:
 forming a mixture with at least one element from Group II of the periodic table, at least one element from Group VI of the periodic table in a container, a first dopant, and a second dopant, wherein the first dopant includes at least one element from Group III or VII of the periodic table, and wherein the second dopant contains erbium (Er) or dysprosium (Dy);   adjusting a concentration of the second dopant in the mixture based on a target depletion characteristic of the semiconductor material; and   converting the mixture into a solid material.   
     
     
         25 . The method of  claim 24  wherein the target depletion characteristic includes a charge carrier mobility and lifetime, and wherein adjusting the concentration of the second dopant includes adjusting a molar concentration of the second dopant based on the target charge carrier mobility and lifetime. 
     
     
         26 . The method of  claim 24  wherein:
 the target depletion characteristic includes a charge carrier mobility and lifetime; 
 the second dopant contains erbium (Er); and 
 adjusting the concentration of the second dopant includes increasing a molar concentration of erbium (Er) in the mixture to increase the charge carrier mobility and lifetime of the semiconductor material. 
 
     
     
         27 . The method of  claim 24  wherein:
 the second dopant contains erbium (Er); and 
 adjusting the concentration of the second dopant includes adjusting a molar concentration of erbium (Er) in the mixture between about 10 to about 400,000 atomic parts per billion. 
 
     
     
         28 . The method of  claim 24  wherein:
 the second dopant contains erbium (Er); and 
 adjusting the concentration of the second dopant includes adjusting a molar concentration of erbium (Er) in the mixture between about 10 to about 10,000 atomic parts per billion. 
 
     
     
         29 . The method of  claim 24  wherein:
 the second dopant contains erbium (Er); and 
 adjusting the concentration of the second dopant includes adjusting a molar concentration of erbium (Er) in the mixture between about 10 to about 20,000 atomic parts per billion. 
 
     
     
         30 . The method of  claim 24  wherein:
 the second dopant contains erbium (Er); and 
 adjusting the concentration of the second dopant includes adjusting a molar concentration of erbium (Er) in the mixture between about 10 to about 200,000 atomic parts per billion.