Subpicosecond transient Raman scattering studies of field-induced electron transport in an In_0.53Ga_0.47As based p–i–n nanostructure: direct observation of the effects of electron momentum randomization

Abstract

Subpicosecond transient Raman spectroscopy has been used to study electron transport properties of an In0.53Ga0.47As based p–i–n nanostructure. Both the electron distribution function and the electron drift velocity have been directly measured as a function of the photoexcited electron–hole pair density. We have found that, at low electron–hole pair densities such as n = 5 × 1016 cm−3, the electron distribution function has an extremely non-Maxwellian shape. However, as the photoexcited electron pair density gradually increases, the non-Maxwellian distribution gradually evolves into a shifted Maxwellian distribution. We attribute these findings to the direct effects of the role of electron–electron scattering in momentum randomization.