Research On The Preparation And Properties Of One-dimensional Nanostructured GeSe₂ Doped With Bi

With the band gap of 2.7 eV, GeSe2 is a wide band gap semiconductor material of IVA-VIA compounds. As a new type of multi-functional material, GeSe2 has caused much attention of the researchers due to its wide application prospect in optical field, electrical field, ion exchange field and many other fields. In this thesis, the resistive switching and piezoresistive effect of Bi-doped GeSe2 nanobelts was studied, in order to develop a brand-new nonvolatile random access memory.GeSe2:Bi nanobelts were synthesized by means of the optimized chemical vapor deposition with the given catalysts. The morphology and structure analysis of the products was characterized by XRD, SEM, TEM and XPS. The field effect transistor(FET) which based on individual GeSe2:Bi nanoblet shows excellent p-type conductivity with hole mobility as high as about 690 cm2V-1s-1.The "Metal-Insulator-Metal"(MIM) nano-structured devices were fabricated, and the RS performance was studied. GeSe2:Bi nanoblets show symmetrical resistive switching(RS) behavior accompany with negative differential resistance. The space charge polarization model is proposed to explain the RS behavior. Moreover, the superior stability, reversibility, nondestructive readout and good cycling performance of the as-fabricated nanodevices demonstrate that Bi-doped GeSe2 nanobelts have the potential for next-generation nonvolatile memory applications.The piezoresistance performance of the devices were studied under both static and dynamic strain. According to the test results, the resistance of the devices laggardly decreased under the compression strain, while sharply increased under the tensile strain.The strain storage properties were studied using a reasonable deformation quantity, strain cycle time of 40 s and triangular wave voltage with the frequency of 0.005 Hz. The test results showed that the GeSe2:Bi nanobelts had excellent non-volatile strain storage properties under tensile strain than under compression strain.The study on nonvolatile random access memory based on individual GeSe2:Bi nanoblet plays an important role in the theoretical direction of the next generation non-volatile storage device.