Research context
This dataset contains the experimental and simulation data underlying all plotted figures (Figs. 2–12) of the publication: Bojarska-Cieślińska, A., Marona, Ł., Grzanka, S., Grzanka, E. & Perlin, P., "InGaN multiquantum wells — problem of carrier injection", Scientific Reports 15, 2902 (2025), DOI: 10.1038/s41598-025-86774-6.
The study addresses the problem of efficient carrier injection into quantum wells in nitride light-emitting structures, particularly InGaN/GaN laser diodes. Because free electron and hole concentrations in nitride materials typically differ by an order of magnitude, and their effective masses and mobilities differ widely as well, carrier distribution across a multi-quantum-well system is often non-uniform: radiative recombination concentrates in the wells located closer to the p-GaN layer, which limits device performance and complicates active-region design. The aim of the work was to determine how quantum barrier thickness, the indium content of individual wells, and their position relative to the p- and n-type regions affect carrier distribution and radiative recombination efficiency. The research was carried out at the Institute of High Pressure Physics, Polish Academy of Sciences (Unipress), Warsaw. The work was co-financed by the European Union under the EIC Pathfinder Open project (CSOC, ID: 101047289) and by the Polish National Science Centre (grant no. 2022/47/I/ST7/03163).
Methodology
The structures were grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) in an Aixtron Close Coupled Showerhead reactor. All samples have a laser-diode-like architecture with graded AlGaN cladding layers. Three sets of samples were prepared. Set A: two nominally identical quantum wells (12–13% In) separated by a quantum barrier 2.5, 5, 10 or 20 nm thick, together with a single-quantum-well reference structure. Set B: two wells with indium contents of 7% and 11% separated by a 5 nm barrier, differing in the position of the deeper well relative to the p- and n-type layers (samples BQW1 and BQW2). Set C: a well with 16% In located near the n-type region and a well with 14% or 11% In located near the p-type region.
Electroluminescence (EL) was measured using the quick indium test method: an n-type contact was formed by scratching the structure with a diamond tip and filling the scratch with indium, while pieces of indium placed on the surface served as p-type contacts; the contacts were annealed on a hot plate at approximately 170°C. Current was supplied by a Keithley 236 source-measure unit, spectra were collected from the top of the structure through an optical fibre and analysed with a SpectraSense 500i spectrometer (Acton, 500 mm focal length, 600 lines/mm grating), and optical power was measured with a Thorlabs S120VC sensor head coupled to a PM100USB power meter. Cathodoluminescence (CL) measurements were performed on the samples from set B. Layer quality and thicknesses were verified by high-resolution X-ray diffraction (HRXRD) using an Empyrean diffractometer (Cu Kα1, hybrid 2-bounce monochromator, triple Ge(220) analyser), recording 2Θ/ω scans of the symmetric 0002 reflection and comparing them with simulated curves. Theoretical modelling — band profiles, carrier concentrations and emission spectra — was performed with the nextnano++ package, which solves the coupled Schrödinger and Poisson equations self-consistently. Threshold currents were measured on laser diodes with uncoated facets operated in continuous-wave (CW) mode. The study did not involve human participants or animals.
Dataset content and structure
The dataset comprises 33 plain-text (ASCII) data files. Each file name begins with the number of the corresponding figure in the article, followed by an identifier of the sample or curve, allowing every figure in the publication to be reproduced. The data include: electroluminescence spectra of structures from sets A, B and C, together with the dependence of emission intensity on barrier thickness (Figs. 2, 7, 11); measured peak emission wavelength and full width at half maximum, alongside the corresponding calculated values (Fig. 3); XRD diffraction curves — both measured and simulated — for samples with 2.5 nm and 20 nm barriers (Fig. 4); calculated electron and hole concentration profiles for four barrier thicknesses (Figs. 5 and 6); cathodoluminescence spectra of the samples from set B (Fig. 8); calculated emission spectra for various combinations of well composition and position (Figs. 9 and 10); and threshold current values for laser diodes with one and with two quantum wells (Fig. 12). Figure 1 (schematic drawings of the structures) and Table 1 (structural parameters) are illustrative and have no corresponding data files.
A detailed file inventory, including the assignment of files to specific samples, column and unit descriptions, measurement conditions and simulation parameters, is provided in readme.txt. The full text of the publication is openly available at https://doi.org/10.1038/s41598-025-86774-6.
