Semiconductor physics

Charge neutrality in semiconductor lasers

Z. N. Sokolova^a, L. V. Asryan<sup>b

a</sup> Ioffe Institute, St. Petersburg
^b Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA

Abstract: A short theoretical review of the problem of charge neutrality in semiconductor lasers is presented. It is shown that the global charge neutrality holds in laser structures at any pump currents both at steady-state and non-stationary conditions. In the context of injection lasers with a low-dimensional active region, the charge neutrality condition reads as equality of the total electron density in a bulk waveguide region and a low-dimensional active region to the total hole density in those regions. It is shown that, due to the fact that at high injection currents each of the electron and hole densities in the waveguide region is significantly higher than each of these densities in the active region, the global charge neutrality condition in the laser structure at such currents effectively reduces to the charge neutrality condition in the bulk waveguide region, and the local charge neutrality in the low-dimensional active region does not have to hold.

Received: 27.10.2025
Revised: 30.10.2025
Accepted: 13.11.2025

DOI: 10.61011/FTP.2025.08.62192.8704