Electrical Properties of the Al/CuInSe<sub>2</sub> Thin Film Schottky Junction

Abstract

The Schottky diode (Al/p-CuInSe 2 /FTO) was fabricated by simple deposition of pure Aluminum on the front side of the CuInSe 2 thin film. We have investigated its electrical characteristics by measuring the current-voltage (I-V), the capacitance-voltage (C-V) and the electrical impedance in the range of temperature (300 K-425 K). At room temperature, this heterostructure has shown nonideal Schottky behavior with 3.98 as ideality factor and 38 μA/cm 2 as a reverse saturated current density. The C-V measured at 100 kHz has shown non-linear behavior and an increase with temperature. Similarly, we have estimated, at room temperature, the carrier doping density, the built-in potential and the depletion layer width which are of about 8.66 × 10 15 cm −3 , 1.12 V and 0.37 μm respectively. By the impedance spectroscopy technique, we have found a decrease with temperature of all the serial resistance R s , the parallel resistance R p and the capacitance C p. The frequency dependence of the imaginary part of this impedance was carried out to characterize the carrier transport properties in the heterostructure. From the Arrhenius diagram, we have estimated the activation energy at 460 meV. An equivalent electrical circuit was used for modeling these results.

CuIn0.7Ga0.3Se2 thin films’ properties grown by close-spaced vapor transport technique for second-generation solar cells

“…They are estimated to be 93.7 Ω and 3.47, respectively. These results are in good agreement with the work in [19]. The higher value obtained for n can be explained by the eventual potential drop and the recombination current through the interfacial layer [19,22,23].…”

“…Chan and Shih [17] have investigated the electrical properties of Al/p-CIS structure using current-voltage (I-V) and capacitance-voltage (C-V) measurements. Furthermore, Tecimer et al [18] have studied the electrical properties of Al/p-CIS/Mo structure and obtained their forward and reverse bias I-V characteristics in a wide temperature range of 100-300 K. Again, Hamrouni et al [19] have investigated the temperature effects on electrical properties of Al/p-CIS/FTO thin-film Schottky junction using I-V, C-V characteristics and the impedance measurements in the temperature range of 300-425 K. Accordingly, the I-V characteristic at (RT) has confirmed that the junction behaves as a Schottky diode. Also, it has been concluded that, the high value of ideality factor, (3.98) which has obtained from dV∕d ln (I) versus the current density at RT, is probably due to both the potential drop and the recombination through the interfacial layer.…”

Fabrications of Hetero-Junction Schottky Diodes by Electrodeposition of Nano-Structured CuInSe2 Materials Using Different Upper Electrodes

“…The forward and reverse current densities of the Al/CuInSe 2 /Mo Schottky diode (measured at 300 K and at +1 V and −1 V) werẽ 0.42 mA/cm 2 and~−0.07 mA/cm 2 , the on/off ratio was~6, and the Φ SH value was 0.729 V. Hamrouni et al electrodeposited the CuInSe 2 films on FTO substrates and annealed them at 400 • C in a vacuum for a duration of 20 min, and the carrier concentration of deposited CuInSe 2 films at 300 K was 8.66 × 10 15 cm −3 . Additionally, Al metal was evaporated on the upper surface of the CuInSe 2 film as a front contact to form the Al/p-CuInSe 2 /Mo Schottky diode [16]. The forward and reverse current densities of the Al/CuInSe 2 /Mo Schottky diode (at 300 K) were 0.151 mA/cm 2 and −0.038 mA/cm 2 , respectively, the on/off ratio was 3.98, and the Φ SH value was~1.22 V. As compared with the two Al/p-CuInSe 2 /Mo Schottky diodes, even our deposited CIS films had the lower value of carrier concentration (N A ), and our investigated Ag/CIS-NRs/p + -Si diode had the larger forward current density of 0.48 mA/cm 2 and an on/off ratio of 8.07.…”

“…For this, the first subject of our research was to grow CIS films (CIS-TFs) and nanorods (CIS-NRs) using an electrodeposition method, and AAO was used as a template for growing the CIS-NRs. A Schottky diode could be easily fabricated by deposition of a pure Al electrode on the CuInSe 2 film [16]. The second subject of our research was to use different conduction materials as the upper electrodes.…”

Revisiting Schottky barriers for CIGS solar cells: Electrical characterization of the Al/Cu(InGa)Se2 contact

“…Different studies of the electrical properties of Al‐CuInSe 2 contacts have been published. The older ones concern with massive CuInSe 2 samples and a few reports about the electrical properties of Al/CIS thin layers contacts have been published more recently ( and references therein). However, the CIS bandgap is only 1.0 eV wide, a value which is rather far from the theoretical optimum value of 1.6 eV for one junction solar cells.…”