Modulation Doping on Electron Raman Scattering in ZnO/MgxZn1−xO Quantum Well

The built-in electric field induced by polarization in ZnO/Mg0.2Zn0.8O quantum wells can be screened to modulate the conduction-band potential profile and intersubband energy levels. To optimize the screening of the built-in electric field, we analyze the influence of an external electric field, temperature, and modulation doping. The position of the doped layer is varied within the heterostructure to improve field compensation, providing additional control over electron localization and intersubband energy separation. In this work, within the effective mass approximation and by self-consistently solving the Poisson and Schrödinger equations using the finite-difference method, we calculate the electronic structure and nonlinear optical response of an n-type doped ZnO/Mg0.2Zn0.8O quantum well heterostructure. Our results indicate a strong dependence of the confinement potential on the applied external electric field and the electrostatic potential arising from the doped layer. We demonstrate electronic Raman gain values on the order of 103–104 cm−1 for specific values of field strength, temperature, and doped-layer position. This approach enables fine-tuning of the nonlinear optical response, which is crucial for the development of ZnO-based optoelectronic devices.