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

Subpicosecond transient Raman spectroscopy has been used to study electron transport properties of an In_0.53Ga_0.47As 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 × 10¹⁶cm^-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.