Impact of the dislocation density on the transient photoluminescence intensity in GaN semiconductor.

Аннотация

The time-resolved photoluminescence in a layer of GaN

with an embedded array of threading dislocations

is studied. An instantaneous spatially uniform source of excitons

is considered. The transport and recombination of excitons is governed by a 3D transient drift-diffusion-recombination equation

with mixed Dirichlet and Robin boundary conditions on the

plane surface and the cylindrical boundaries of the dislocations.

We develop a stochastic simulation algorithm which solves this

problem by tracking exciton trajectories. The drift of the excitions

is affected by the piezoelectric fields around the dislocations.

The parameters of the piezoelectric field, the exciton's diffusion length and its mean life time are taken from the experimental study published recently in our triple article in Physical Review Applied of 2023. The main finding in the present paper concerns the relation between the photoluminescence intensity and the dislocation density. It is shown that from a transient photoluminescence curve it is possible to extract the dislocation density with high resolution.