Research Data Supporting 'Multi-microscopy Characterisation of Cu(In,Ga)S₂ Absorbers for Future Tandem Solar Cells'

This a research data asscoiated with Yucheng Hu's PhD Thesis. Scanning electron microscopy (SEM) - energy dispersive spectroscopy (EDS) was performaned with an operating voltage of 7 kV and 20 kV, using an oxford instrument EDS detector. X-ray Diffraction (XRD) was performed using Cu-Kα radiation and the data was plotted without applying instrumental resolution correction. Glow discharge optical elementary spectroscopy, (GDOES), the in-depth compositiona measurements is performed using an argon plasma at a pressure of 450 Pa to erode the sample and generate a light emission of the sputtered atoms. The specific emission lines of the single elements are optically diffracted and detected by several photomultipliers. Photoluminescence (PL), was performed by a home-built absolute PL set-up equipped with a 405 nm laser excitation source at room-temperature using a CCD Si detector. The incident photon flux was matched to a 1 sun spectrum above the bandgap of the absorber. Time-resolved transient photoluminescence (TRPL) was performed using a time-correlated single photon counting system with 638 nm wavelength pulsed laser at a reptition rate of 10 MHz, detecting the band edge emission with a bandwidth of 46 nm. The CL measurements were carried out by using an Attolight Allain 4027 Chronos dedicated CL-SEM at room temperature. The CL measurements on the bevel and cleaved cross sections were done with a 5 kV electron beam with a 100 µm and a 50 µm aperture, respectively. The plan view CL measurements were carried out with a 10 kV electron beam and a 50 µm aperture. The dwell time per pixel for all measurements was 250 ms. CL data was processed using open-sourced python library, hyperspy and lumispy. The EBSD measurements were carried out on a Zeiss Gemini 300 SEM equipped with an Oxford Instruments HKL Symmetry 3 EBSD detector. All measurements used a 15 kV electron beam, a 50 ms pixel exposure time, and a 40 nm pixel step size. The EBSD indexing was carried out by Aztec HKL software, employing Hough-based indexing with a zinc blende cubic lattice (a = b = c = 5.58 Å). The EBSD analysis was carried out using the MATLAB toolbox MTEX. Scanning transmission electron microscopy (STEM) images were acquired on a probe-corrected Thermo Fisher Spectra 300 S/TEM operated at 300 kV. The STEM-EDS signal was collected with a Dual-X system comprising two detectors, one on either side of the sample, for a total acquisition solid angle of 1.76 sr. Compositional maps were acquired using Velox, with repeated raster scanning and a probe current of ∼150 pA. Elemental maps (Figure S9c) were produced with Velox. The 4-dimensional scanning transmission electron microscopy (4D-STEM) data was recorded on the same microscope as STEM-EDS, at 300 kV, with a camera length of 38 mm, step size of 2 nm and pixel time of 0.02 s. 4D-STEM data processing was carried out with two open-source Python libraries, pyxem and py4DSTEM. The current-voltage (I-V) data was recorded at room temperature in the forward scan direction using an IV source measure unit with a scan speed of 50 mV/sec. The entire active area was illuminated with 1 sun illumination (100 mW/cm2) during the measurement without any mask. The I-V is automatically converted to J-V results with input active area of about 0.42 cm^2. EQE was measured using chopped illumination from a halogen-xenon lamp (Xenon short ARC lamp, Ushio uxl-302-0) and a lock‐in amplifier to measure the photocurrent. AFM and TUNA data collected by Bruker Dimension Icon Pro AFM. AFM data processed by Bruker Nanoscope Analysis software and python library PySPM.