The highest efficiency of 3.93% with good cell-to-cell uniformity was achieved when the absorber thickness was ~1.2 µm. The good stability of the best device was also confirmed under continuous...

Several procedures for Fourier analysis of single diffraction peaks for microstrains and mosaic sizes are compared. A simple new method works well, especially when the size distribution is broad, and/or when the strains vary in an unusual manner.

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In this investigation an attempt has been made to correlate the experimentally observed X-ray diffraction profile from imperfect solids with the one obtained theoretically from an approach of simultaneous convolution of the true diffraction profile resulting from the imperfection content of the materials and the instrumental profile, considering realistic distribution functions. The expressions for the intensity distributions are derived from the simultaneous convolution of Schoening's true profile (originating from the Gaussian strain profile and the Cauchy crystallite-size profile) and the instrumental profile having either Gaussian or Cauchy functional forms, and the theoretical forms are compared to those observed from some silver-and copper-base cold-worked alloys and vapour-deposited thin silver films. The agreement is fairly good for both first-and second-order reflections with small deviations in the tail region, which may arise from uncertainty in the background-level estimation, consideration of functions purely symmetrical in form and neglect of absorption and TDS effects. A further agreement of Schoening's true profile with Stokes's corrected deconvoluted true profile implies the validity of Schoening's approximation.

Compositionally uniform high crystalline quality Al0.45Ga0.55N nanoflowers have been synthesized by MOCVD for application in high-performance ultraviolet-C photodetectors. The photodetectors fabricated with nanoflowers displayed a photoresponsivity of ∼0.72 A W−1 along with a sensitivity of ∼40% at 2 V bias in the ultraviolet-C region.

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The replacement of CdS buffer layer is desirable for the development of nontoxic, environmentally friendly kesterite thin-film solar cells (TFSCs). Recently, several ternary compound semiconductors have been extensively investigated as an alternative buffer layer for Cd-free TFSCs. Herein, the effectiveness of (NH 4 ) 2 S treatment on the surface properties of the absorber, as well as the device performance of atomic layer deposited (ALD) Zn(O,S) buffer-based CZTSSe solar cells, has been investigated. X-ray photoelectron spectroscopy (XPS) results showed that the elemental compositions of CZTSSe surface were significantly influenced by (NH 4 ) 2 S treatment, whereas the surface morphologies of the CZTSSe-absorber layers remained unaffected. The XPS results further suggested that the (NH 4 ) 2 S solution treatment substantially removed the native oxide layer from the CTZSSe absorber surface. The fabricated CZTSSe/Zn(O,S) device without (NH 4 ) 2 S treatment displayed an initial cell efficiency of 7.46%. The energy conversion efficiency increased significantly to 9.82% after the (NH 4 ) 2 S treatment of absorber layers for an optimum duration of 1 min; to the best of our knowledge, this is the highest efficiency achieved to date for Zn(O,S) bufferbased kesterite solar cells. The improved device performance is predominantly attributed to the pronounced increase in the fill factor (FF) of TFSCs resulting from the removal of oxides/hydroxides from the CZTSSe surface and passivation of absorber surface with sulfur species. However, increasing the treatment duration to 3 or 5 min resulted in the deterioration of cell efficiency, primarily due to the progressive degradation in the FF of the device. This study demonstrates a plausible route to improve the performance of Zn(O,S) buffer layer-based kesterite solar cells through a simple surface treatment of the absorber layers using (NH 4 ) 2 S solution.

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