Transporte eletrônico em amostras de InAs/GaAs

Abstract

This work presents the study of electronic transport on a set of five multilayer molecular beam epitaxy-grown InAs/GaAs semiconductor samples. We developed an automated switch system to carry out electronic transport measurements of mobility and carrier concentration using the van der Pauw technique. The system was evaluated using an ITO sample, which is well known in the literature. In its evaluation, the system presented results consistent with the expected ones. Measurements were carried out as a function of temperature within the range of 260 K to 310 K. To identify which scattering mechanisms most contributed to mobility limitation, It was necessary to use the Self-adaptive Differential Evolution meta-heuristic method. This method allowed the determination of the main scattering mechanisms limiting the electronic mobility and identified as scattering by dislocations and phonons. Dislocations consist of the dominant defects in this lattice mismatch structure. Therefore, to increase carrier mobility, we propose some strategies: a change in the sample growth parameters such as substrate temperature and InAs/GaAs layer thickness. Alternatively, annealing of the samples could also be considered to improve sample mobility.