Mobility spectrum computational analysis using a maximum entropy approach

Abstract

A method to calculate a smooth electrical conductivity versus mobility plot ("mobility spectrum") from the classical magnetoconductivity tensor in heterogeneous structures with the help of a "maximum entropy principle" has been developed. In this approach the closeness of the fit and the entropy of the mobility spectrum are optimized. The spectrum is then the most probable one with the least influence of the personal bias of the investigator for any given set of experimental data and is maximally noncommittal with regard to the unmeasured data. The advantages of the maximum entropy mobility spectrum analysis as compared to the conventional mobility spectrum analysis are demonstrated using a synthetic dataset.

Experimental Demonstration of Room-Temperature Spin Transport inn-Type Germanium Epilayers

“…5(a)]. Furthermore, the temperature dependence of the mobility of the n-Ge channel μ n-Ge was determined using maximum-entropy mobility spectrum analysis [60,61]. The mobility in the n-Ge channel changed from 210 AE 30 cm 2 V −1 s −1 at RT to 376 AE 30 cm 2 V −1 s −1 at 130 K [see Fig.…”

Extremely high room-temperature two-dimensional hole gas mobility in Ge/Si0.33Ge0.67/Si(001) p-type modulation-doped heterostructures

“…To solve this problem the magnetic field dependences of the magnetoresistance and Hall resistance at 295 K were measured and MSA was applied. MSA was proposed by Beck and Anderson, 7 and was further developed by Dziuba et al, 8 by Antoszewski et al, 9 by Vurgaftman et al, 10 and by Kiatgamolchai et al 11,12 as a useful technique for analyzing multi-carrier galvanomagnetic phenomena. MSA is the transformation of the electrical conductivity tensor versus the magnetic field into the conductivity density versus the mobility spectrum.…”

“…After that an average was taken and the magnetoresistance and Hall resistance were converted into conductivity tensor components xx (B) and xy (B) followed by a maximum entropy-MSA ͑ME-MSA͒ fit procedure. 11,12 It is worth pointing out that the ME-MSA approach does not require any preliminary assumptions about the number of different types of carriers and this aspect is very important for transport phenomena analysis in semiconductor structures.…”

Origin of conductive surface layer in annealed ZnO

“…7 However, if more than two layers are important, or potentially important, then complicated algorithms are necessary to effect a solution. [8][9][10] In practice, if the surface and bulk mobilities are high enough, say ജ1000 cm 2 / V s, then the magnetic-field-based methods can be implemented with common laboratory magnets, of magnetic-field strength ͑B͒ on the order of 1 T. However, for ZnO at room temperature, or very low temperatures, mobilities are typically low enough that much higher fields ͑B ജ 10 T͒ are necessary to ensure accurate results. Even with B = 10 T, it would be difficult or impossible to characterize surface layers with mobility ഛ1 cm 2 / V s and indeed we find such low mobilities under certain annealing conditions, including those of the present work.…”