Effect of Ga/Cu Ratio on Polycrystalline Thin Film Solar Cell

Abstract

Structural and electrical properties of polycrystalline CuGaSe2thin films have been studied by changing the Ga/Cu ratio in the films. CuGaSe2thin films with various Ga/Cu ratio were grown over Mo-coated soda-lime glass substrates. With the increase of Ga content in CuGaSe2, morphology of the films was found to deteriorate which is associated with the smaller grain size and the appearance of impurity phases presumably due to the phase transition from the chalcopyrite structure to the defect-related phase on the surface of the films. Properties of the Ga poor films were affected by the Cu rich secondary phases. Electrical properties of the films were strongly influenced by the structural properties and degraded with increasing the Ga/Cu ratio in the film. Device performances, fabricated with the corresponding CuGaSe2films, were found to be correlated with the Ga/Cu ratio in the films and consistent with the observed structural and electrical properties.

Investigation of low-cost magnesium stannate transparent conductive oxide layer: optical, structural and electrical properties and photovoltaic applications

“…On the other hand, loss of oxygen from the crystal will also produce the interstitial tin atoms which results in Sn1+xO in the matrix. This means that the intrinsic donor can be increased by the vacuum annealing process and thus, increase the conductivity [40,41]. The unwanted elements presented are Ca, Na, C, in the values of 4.31%, 2.92%, 2.24%, 3.21%, Ca-5.14%, Na-3.12% and Si -1.70%.…”

“…All carriers are possessing the carrier concentration of the order of 10 20 cm 3 for the samples of higher ratio tin, increase slightly as the thickness increases, reflecting that longer spraying time may cause more substantial MgSnO3 or more oxygen vacancies. This is because the MTO film with reduced thickness is associated with poor crystallinity having various imperfections owing to large stress, and many free electrons then are caught by large numbers of traps formed by these defects, since the Mg concentration of all the films is about 0.1 wt% (determined by XRD, FESEM) [39][40][41].…”

“…Figure 8 (b, c, d) shows Nyquist plots of S3C -DSSC, S4C-DSSC, S5C-DSSC and Table5shows the values of efficiency for every fabricated cell and all the measured parameters. Practically in these EIS spectra three characteristic semicircles has been represented by the Nyquist plot for a fabricated DSSC[40,41]. The MHz region represented by small semicircle in the spectra and this lower frequency region allocated to the Nernst diffusion of I3-within the electrolyte.…”

Characterization of Cu(InGa)Se2 (CIGS) thin films in solar cell devices

“…Quantitative analyses of CIGS layers have accordingly been performed by many research groups via various analytical methods including inductively coupled plasma‐atomic emission spectrometry (ICP‐AES), SIMS, sputtered neutral mass spectrometry, x‐ray fluorescence (XRF), electron probe microanalysis (EPMA), glow discharge mass spectrometry, micro‐proton induced x‐ray emission, AES, XPS, energy dispersive spectroscopy, and x‐ray diffraction . Among these techniques, dynamic SIMS is a useful method to measure trace elements and the ratio of elements comprising the CIGS layer.…”

Structural, Optical and Electrical Properties of Ga Doped ZnO/Cu grid/Ga Doped ZnO Transparent Electrodes

“…2 Impurity doped ZnO is one of the promising transparent conductive oxide (TCO) materials due to its merit such as low cost, nontoxic and stability in hydrogen plasma [1][2][3][4][5] . For application of TCO films to devices such as organic solar cell, it is necessary to prepare TCO films at low temperature such as room temperature (RT) [6,7] .…”