Title: Next generation ultrawide bandgap semiconductor thin film deposition and diode fabrication for optoelectronics and energy devices
Research proposal No: 1.1.1.9/LZP/2/25/197
Duration: 20.02.2026. - 19.02.2029.
Project Leader: Ph.D. Esme Isik
Total budget: 184 667.60 EUR
Project aim:
The main research goal of this project is to produce Schottky barrier and p-n heterojunction diode structures based on semiconductor rutile GeO2 thin films, reaching TRL 3 (experimental proof-of-concept).
Project description:
Adoption of ultrawide bandgap semiconductors in energy devices could significantly reduce the global energy consumption, as well as enable new applications in far-ultraviolet optoelectronic devices in many high-tech sectors. Rutile germanium oxide (rGeO2) has recently emerged as a potential bipolar semiconductor, which could overcome many of the fundamental and technological issues existing in other wide and ultrawide bandgap materials. The objective of this applied research project is to establish n-type rGeO2 thin film deposition technology and to produce Schottky barrier and p-n heterojunction diode structures based on the material, reaching TRL 3 (experimental proofof-concept). The expected results encompass new scientific knowledge on GeO2 rutile phase stabilization on different heteroepitaxial substrates, new technological knowledge on rGeO2 integration with different metals and p-type materials in heterojunctions, as well as demonstration of a diode structure based on this novel UWBG material, including its full electrical and photoelectrical characterization. The project will be realised at Institute of Solid State Physics, University of Latvia, from 20.02.2026 until 19.02.2029, with a total budget of 184 667.60 EUR.
PROJECT PROGRESS
Time period: 02.2026. – 08.2026.
The PLD growth methodology for rGeO₂ thin films was established. Undoped and n-type doped rGeO₂ films were deposited on r-, m-, and a-plane sapphire substrates to investigate the effect of substrate orientation on rutile phase formation, crystalline quality, and film morphology. Deposition parameters were systematically varied to establish reproducible growth conditions.
The structural, morphological, chemical, and optical properties of the deposited films were investigated using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry. These measurements provide the basis for correlating growth conditions and substrate orientation with film properties and dopant incorporation.
Initial development of rGeO₂-based Schottky barrier diodes (SBDs) was initiated. Device mask layouts were designed and prepared, followed by fabrication of initial test structures under cleanroom conditions to establish the lithography, metallization, and device-processing workflow.