Preparation Of Nanometer Semiconductor Gas Sensing Materials And Nature Study

In this paper, we prepared pure and Cu, Pd, Pt dopednanome ter--s ized powders by 1 iquid--phase chemica l meansand inves t igated samp1es wi th XRD, TGA, DTA, IT--RT and SEM.The preparing process, the structure and thecharacter izat ion of the samples were s tudied. The effectof prepar ing condi t ions, doping cofltent and doping meanson the products were al so studied. We invest igatedsamp1es' gas--sens ing character izat ion and i t s res is tancea t l ow t empera ture.These were resul ts: 1) Thc part icle s ize of the pureand doping samp1e was less thafl 30 nano--meter. 2) Theconcentrat ion of start ing solut ions could affect thesamp1es's ize, and so did the heat--trea tment temperature,it might not higher than 600C. 3) Doped with Cu0 theproduct s was Cu0--Sn0, so1 id--solut ion, but when the contentof Cu0 doping was higher, the product was the mixture ofCu0--Sn0, sol id--solut ion and Cu0 phase. 4) Doping cou1dres tra in par t ic1es' growing, the samples's ize became 1esswi th surface coat ing, and pre--treatment temperature forthe dry--ge1 of samples for coating was not suitable if itwas too high. 5) The samples with Pd doping had bettersens it ivi ty and se1ect ivi ty. For the co--doping ma ter ia l s,the sens it ivi ty increased wi th the doping content, and thesens i t ivi ty of surface--coat ing was bet ter than that of theco--doping. But the doping content of surface--coat ing wasunfi t to be too much. 6) The Sn0, sample with 1 ittlepar t ic 1 e s ize was semi--conductor when the temperature wasI Ifrom 390K to 50K, and its conduct ivi ty character izat ionwas meta1--1 ike when the temperature was 1ower than 50K,whi 1e for the much bigger-- s ized samp1e, the conduct ivi ty.was semi--conductor dur ing the whol e range. 7) Dopingincreased the samp1es' res is tance, the convers ion fromsemi--conductor to insulator took p1ace, and theconver t ing tempera ture of surface--coa t ing samp1 es wash i gher.