Work

Enhanced near-infrared absorption in lattice-matched Sc0.14Al0.86N/GaN multi-quantum wells: growth optimization and insights into polarization parameters

Year: 2024

Type: article

Abstract: We report on the near-infrared intersubband (ISB) absorption properties of strain-free Sc0.14Al0.86N/GaN multiple quantum wells (MQWs) grown on c-plane GaN substrates by molecular beam epitaxy. These MQWs exhibit strong, sharp, and tunable absorption energies between 515 meV and 709 meV, for well widths ranging from 7 nm to 1.5 nm, respectively. Observation of ISB absorption in ultra-thin Sc0.14Al0.86N/GaN MQWs not only extends the near-infrared range accessible with Sc-containing nitrides but also highlights the challenges of growing nanometer-thick GaN quantum wells. We explore the effects of growth temperature on absorption characteristics and find that substrate temperatures above 600°C significantly enhance ISB absorption intensity but also introduce an energy redshift for the narrowest wells. The redshift is attributed to increased interface roughness due to ScAlN surface morphology degradation at higher temperatures. Additionally, a comparison of experimental results with simulated band-structures indicates that the magnitude of net polarization rises faster with Sc-composition than previously suggested by theoretical calculations. This study advances the prospects of ScAlN/GaN heterostructures for novel photonic devices in the technologically important near-infrared range.

Source: Optical Materials Express

DOI: 10.1364/ome.545820

Authors: Zain Ul Abdin, Govardan Gopakumar, Rajendra Kumar, Michael J. Manfra, Oana Malis

Institution: Purdue University West Lafayette

Language: English

Topic: GaN-based semiconductor devices and materials

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,843

Funder: National Science Foundation