CuInSe2(CIS) thin films are successfully prepared by electron beam evaporation. Pure Cu, In, and Se powders were mixed and ground in a grinder and made into a pellet. The pallets were deposited via electron beam evaporation on FTO substrates and were varied by varying the annealing temperatures, at room temperature, 250°C, 300°C, and 350°C. Samples were analysed by X-ray diffractometry (XRD) for crystallinity and field-emission scanning electron microscopy (FESEM) for grain size and thickness. I-V measurements were used to measure the efficiency of the CuInSe2/ZnS solar cells. XRD results show that the crystallinity of the films improved as the temperature was increased. The temperature dependence of crystallinity indicates polycrystalline behaviour in the CuInSe2films with (1 1 1), (2 2 0)/(2 0 4), and (3 1 2)/(1 1 6) planes at 27°, 45°, and 53°, respectively. FESEM images show the homogeneity of the CuInSe2formed. I-V measurements indicated that higher annealing temperatures increase the efficiency of CuInSe2solar cells from approximately 0.99% for the as-deposited films to 1.12% for the annealed films. Hence, we can conclude that the overall cell performance is strongly dependent on the annealing temperature.
Articles you may be interested inSelective wet etching of lattice-matched InGaAs/InAlAs on InP and metamorphic InGaAs/InAlAs on GaAs using succinic acid/hydrogen peroxide solution A new dry photochemical etching process using HBr gas to selectively remove InGaAs layer over an InAlAs layer has been developed. A 172 nm Excimer lamp was used as the photon source for this experiment. The intensity of the 172 nm light on the surface of the samples was 3 mW/cm 2 . Etch rates of 62 Å/min and 0.61 Å/min are obtained for InGaAs and InAlAs, respectively, at a chamber pressure of 120 mTorr, sample temperature of 80°C and HBr flow rate of 10 sccm. These rates translate into a selectivity of over 100 for this material system. Scanning electron microscopy pictures and visual inspection reveal that this process is almost damage free, compared to reactive ion etching. This is due to lack of ion bombardment in the photochemical process. X-ray photoelectron spectroscopy analysis suggests that the etch selectivity mechanism is due to the formation of nonvolatile Al 2 O 3 on the surface of the InAlAs layer. This etching system should be very useful for fabrication of electrical as well as optical devices based on InGaAs/InAlAs heterojunction.
Articles you may be interested inPower loss measurements in quasi-1D and quasi-2D systems in an In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As heterostructure Reactive ion etch-induced effects on 0.2 μm T-gate In0.52Al0.48As/In0.53Ga0.47As/InP high electron mobility transistors J.Optimization of reactive ion etching of Al0.48In0.52As in CH4/H2 by the experimental design method In order to improve the Schottky diode characteristics of metal-In 0.52 Al 0.48 As, a new dry photochemical etching and sulfur passivation process has been developed. Excimer and deep UV lamps were used for photochemical etching and surface passivation, respectively. Auger electron spectroscopy measurement shows that this passivation process is as good as wet ͑NH 4 ͒ 2 S x and P 2 S 5 /͑NH 4 ͒ 2 S passivation in terms of sulfur coverage. Schottky diodes were fabricated on n-In 0.52 Al 0.48 As by electron beam evaporation of a multilayer metal contact of the form Mo/Ti/Pt/ Au ͑2/30/300/200 nm͒. The leakage current has been reduced by three orders of magnitude after applying this passivation process. X-ray photoelectron spectroscopy measurements illustrate that these free S* radicals are capable of replacing As-O and In-O bonds to As-S and In-S bonds. The conclusion is that the As-O and In-O bonds are the primary causes of leakage current. These bonds are dissolved after this photochemical sulfur surface passivation.
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