2026-2027 Faculty Research Grants

Henry Navarro and Brendan Cross (Physics). 

Optoelectronic Relaxation Dynamics in III–Nitrides and Halide Perovskites for Light Controlled Electronic Devices.

This project studies the electrical response to illumination, the relaxation dynamics, and the volatile and non-volatile behavior of two complementary types of materials, bulk III-nitride thin films (InN, GaN, AlGaN on Al₂O₃) and mixed-cation halide perovskites based through a new collaboration with Hope College, which is providing the latter type of materials for us. These material systems present advantages for reconfigurable and energy-efficient optoelectronic applications, based on (1) tunable bandgaps in which one can access the whole visible spectrum and beyond, (2) strong light-matter interactions, (3) carrier dynamics dominated by defects. A key advantage of this proposal is that all III–N samples have already been synthesized and are available in our Nanoscience & Materials Laboratory, enabling immediate measurement using Andrews University’s new electrical transport and optoelectronic characterization station. Using this system, we will measure carrier properties, photoconductive rise and decay curves, extract relaxation times, and determine whether each material exhibits volatile (fastrecovering) or nonvolatile (persistent) photoinduced electronic states. The perovskites from Hope College are mixed-cation FA_xCs_1-xPbBr₃ thin films (typically 0 < x < 0.15) prepared with PEABr additive to reduce pinholes and improve crystallinity. These compositions modify Br⁻ stoichiometry, enhance charge transport, and improve optical response, making them ideal for light-response and relaxation studies. By directly comparing these distinct materials, the project aims to establish universal principles linking composition, microstructure, and interfacial chemistry to dynamic optoelectronic behavior.