On the analysis of island shape evolution from diffuse x-ray scattering of organic thin films and the implications for growth

TL;DR

This paper investigates the microscopic evolution of island shapes in organic thin films during growth, using GISAXS data modeled with scattering theory, and confirms findings with AFM measurements, providing insights for optoelectronic device fabrication.

Contribution

It introduces a detailed modeling approach for island shape evolution in organic thin films using GISAXS data and theoretical scattering models, validated by AFM.

Findings

Island shapes change across layers as modeled by scattering theory

GISAXS effectively captures morphological evolution during growth

AFM measurements confirm the modeling results

Abstract

Understanding the growth of organic semi-conducting molecules with shape anisotropy is of high relevance to the processing of optoelectronic devices. This work provides insight into the growth of thin films of the prototypical rodlike organic semiconductor diindenoperylene on a microscopic level, by analyzing in detail the film morphology. We model our data, which were obtained by high-resolution grazing incidence small angle x-ray scattering (GISAXS), using a theoretical description from small angle scattering theory derived for simple liquids. Based on form factor calculations for different object types we determine how the island shapes change in the respective layers. Atomic force microscopy measurements approve our findings.