Influence of Al-doped ZnO Transparent Contacts Deposited by a Spray Pyrolysis Technique on Performance of HIT Solar Cells

AbstractTransparent and conductive Al-doped ZnO (AZO) thin films were deposited by spray pyrolysis and analysed in the aim to improve optical and electrical properties involved in the efficiency of Heterostructure with Intrinsic Thin Layer (HIT) solar cell. X-ray diffraction measurement shows that AZO film grown on glass has (002) preferred orientation. High optical transmittance value of ∼80% in the visible region was observed and the optical band gap was found to be 3.31eV at room temperature. The influence of AZO thin films as transparent conductive oxide TCO on heterojunction with intrinsic thin-layer (HIT) solar cell performance was investigated using software simulation. The beneficial effect of implementing AZO front contact for increasing electrical energy conversion properties of HIT solar cell compared to the reference cell without the AZO layer

Structural, electrical and optical properties of Al–Sn codoped ZnO transparent conducting layer deposited by spray pyrolysis technique

International audienceLow cost Al-Sn codoped ZnO (ATZO) Transparent Conductive Oxide films were deposited by spray pyrolysis on glass substrate. The influence of Al-Sn codoping on the structural, optical and electrical properties of ZnO thin films was studied by comparing the same properties obtained in undoped ZnO, Al doped ZnO (AZO) and Sn doped ZnO (TZO) thin films. The so-obtained films crystallized in hexagonal wurtzite structure. The morphology and structural defects have been investigated by both High resolution Field Effect Scanning Electron Microscopy (FE-SEM) and Raman spectroscopy at 532 nm excitation source. In the visible region, the undoped and doped films show an average transmittance of the order of 85%, while for ATZO thin film, it is of the order of 72%, which points out a degradation of the optical properties due to the co-doping. The optical band gap of ATZO thin film achieves 3.31eV and this shift, compared to the referred samples is attributed to the Burstein–Moss (BM) and band gap narrowing (BGN) opposite effects which is due to the increase of the carrier concentration in degenerate semiconductors. Within all the samples, the ATZO thin film exhibits the lowest electrical resistivity of 4.56 × 10−3 Ωcm with a Hall mobility equal to 2.13 cm2 V−1s−1, and the highest carrier concentration of 6.41 × 1020 cm−3. The performance of ATZO transparent conductive oxide film are determined by its figure of merit (φTC), found equal to 1.69 10−4 Ω−1, which is a suitable value for potentially high-performance solar cell applications

Electrical Characterization of n-ZnO/p-Si Heterojunction Prepared by Spray Pyrolysis Technique

AbstractThe study reports the experimental and the electrical junction properties analysis of current–voltage characteristics of n-ZnO/p-Si heterostructures. Wide band gap semiconducting layer of n-type ZnO thin film was fabricated on p-type Si wafer with spray pyrolysis technique at 550C° to form n-ZnO/ p-Si heterojunctions. The current-voltage characteristic of the n-Zn0/ p-Si heterojunction device has been measured at room temperature in the dark and under illumination (lamp/160W). The characteristic parameters of the structure such as barrier height, ideality factor and series resistance were determined from the current-voltage measurement

Structural, Optical and Electrical Properties of Sn-doped Zinc Oxide Transparent Films Interesting for Organic Solar Cells (OSCs)

International audienceTin doped zinc oxide firms were prepared on glass substrates by spray pyrolysis

Optical, electrical and structural properties of nano-pyramidal ZnO films grown on glass substrate by spray pyrolysis technique

International audienceOptical, electrical and structural properties of ZnO nano-pyramidal films, synthesized by chemical spray pyrolysis technique on glass substrates were investigated. A complete set of structural, optical and electrical parameters is proposed in this contribution. ZnO films possess polycrystalline wurtzite structure showing a preferential orientation along the c-axis as confirmed by XRD measurements. The structure has been investigated by using Raman spectroscopy, at 532 nm excitation source and the morphology is characterized by scanning electron microscopy (SEM). Link to the specific growing parameters, the morphology of the so-obtained films is rarely observed in nanostructures family with a diameter of ZnO hexagonal nano-pyramids in the range of 50–150 nm smaller than this usually obtained by spray pyrolysis. The strong peaks of the E2 Raman mode at 99.3 cm−1 (low) and 439.4 cm−1 (high), indicate a good crystal quality of the ZnO nano-pyramids. The existence of a compressive stress in the ZnO structure was pointed out by Raman scattering and estimated by XRD measurements. High optical transmittance value of the film above 90% in the visible region was observed and the optical band gap was found to be 3.273 eV at room temperature. The photoluminescence (PL) spectrum of ZnO hexagonal pyramid shows an intensity ratio of the UV emission to the visible band more than 20. By electrical characterizations of the ZnO films, we obtained the values of the resistivity and Hall mobility equal to 17 Ω cm and 8.49 cm2 V−1 s−1, respectively

Doped ZnO Thin Films Properties/Spray Pyrolysis Technique

International audienceIn this contribution, the effect of different dopants (Al, Sn, and Cu) on the structure, texture and optical properties of ZnO thin films was investigated. Al-doped ZnO (AZO), Sn-doped ZnO (TZO) and Cu-doped ZnO (CZO) thin films are synthesized by chemical spray pyrolysis technique on glass substrates. The so-obtained films crystallized in hexagonal wurtzite polycrystalline structure. The pole figures show that all the thin films have (0002) as the preferred orientation along the c-axis with the highest level was obtained in TZO thin film. The morphology film was significantly affected by the doping type. The transmittance spectra of all the films point out highly transparent in the visible range with an average transmittance higher than 80% for TZO and AZO films but with an average transmittance equal to about 70% for CZO film. Furthermore, the optical bandgap values were determined by the Tauc's law and were found to be 3.30 eV, 3.28 eV and 3.27 eV for AZO, TZO, and CZO thin films, respectively. The Urbach energy of the films was also calculated