Characterization Of Nanometer Semiconductor Materials Based On SPM

Abstract:The external performance of quantum optoelectronic devices such as quantumdot lasers is governed by their inner workings-as described by the spatial profiles ofcarriers and surface potentials. Without an experimental means of probing these innerdistributions, the chief mechanisms responsible for quantum devices performance remainspeculative at best. For example in quantum cascade detector materials,what factors related tomacroeconomic performance after the device is made. But specific internal substrate wedon’t know but only by means of electron microscopy and AFM. In this thesis, We have made very detailed measurements on the buffer layer and theactive region.We use tetramethyl ammonium hydroxide solution to etch cleavage of thesample.Then We use Contact mode AFM do a very detailed scan test on the sample.AndWe obtained sample topography of buffer layer and the active region,which is3um×3um.But the test on the active region is failed. We summarize experiences and find improved methods,such as polishing and usingBrooke Icon AFM instrument. Then we made a series test on quantum cascadestructure. And we obtained periodic active area topography, the distribution of resistivitycontour map and one-dimensional lateral distribution of the resistance curves. At last we learned the initial dopant concentration of the substrate relative to the sizeof the buffer layer and the active region.