Monitoring HIOS growth: in-situ and real-time X-ray scattering
Objectives
The crystal quality and the morphology at the inorganic / organic interface play a crucially important role for the functionality of HIOS devices. Therefore, by using different in-situ x-ray and optical measurements, our goal is to:
- determine the crystal structure, orientation (lying down / standing upright) and the growth-mode (Volmer-Weber, Stranski-Krastanov, layer-by-layer) of organic molecules on top of inorganic semiconductors like ZnO and GaN
- monitor the evolution of molecular orientation and strain
- model HIOS growth and calculate atomistic details such as the kinetics of interlayer molecular diffusion
- understand the influence of growth parameters like film thickness, temperature and molecular flux on the organic film quality and its properties and optimize them for functional optoelectronic applications
Fig. 1: Examples for processes and parameters of HIOS growth that we want to investigate and analyze by means of x-ray scattering.
Methods
- growth of organic films by organic molecular beam deposition (OMBD)
- x-ray reflectivity (XRR)
- grazing incidence x-ray diffraction (GIXD)
- optical measurements, e.g. differential reflection spectroscopy (DRS), Raman and fluorescence spectroscopy
Experimental set-up
Fig. 2: Mobile UHV-chamber with windows for x-ray and optical access inside an EFG diffractometer for in-situ XRR, GIXD and optical measurements.
