Enhancing Light Emission with Electric Fields in Polar Nitride Semiconductors

Significant effort has been devoted to mitigating polarization
fields in nitride LEDs, as these fields are traditionally viewed as
detrimental to light emission, particularly for red emission. Contrary
to this prevailing notion, we demonstrate that strong polarization
fields can enhance the optical-transition strength of red-emitting
AlInGaN quantum wells, which has been historically challenging to
achieve. By leveraging machine-learning surrogate models trained on
multiscale quantum-mechanical simulations, we globally explore the
heterostructure design space and uncover that larger fields correlate
with higher electron–hole overlap. This relation arises from
the quantum-confined Stark effect, which enables thinner wells without
requiring higher indium compositions, thus overcoming a key limitation
in nitride epitaxy. Structural and compositional engineering of internal
fields offers a unique dimension for designing polychromatic nitride
LEDs, crucial for miniaturizing LED pixels to the micrometer scale
for extended-reality and biomedical applications. Broadly, our work
demonstrates how machine learning can uncover unexpected paradigms
for semiconductor design.