Space-charge-limited currents as a technique for the study of imperfections in pure crystals

This work represents experimental and theoretical investigations on the electrical characteristics of ZnS nanocrystalline thin films synthesized via sonicated (UCBD) and un-sonicated (CBD) chemical bath deposition technique and the fabrication of Schottky junction diodes, for potential solar cell incorporation and other opto-electronic applications. The sonication induced ZnS nanocrystalline thin films (SNP) at frequency 20 kHz–1 MHz and without sonication induced ZnS nanocrystalline thin films (NP) deposited on an indium tin oxide (ITO) substrate. A rapid thermally evaporated lightly doped Ag on SNP and NP-ZnS transparent thin films in the high range of vacuum (~10−6 Torr), has been achieved. The current density-voltage (J-V) and capacitance-voltage (C-V) measurements of fabricated Schottky diodes were carried out employing a potentiostat device. The enhanced performance of fabricated Schottky devices has been quantified by analyzing their J-V characteristics using established Landauer transport formalism. Ideal diode behavior has been confirmed by a low voltage drop of 0.35 V, and low junction capacitance ~3.21 nF across fabricated Schottky diodes. The maximum blockage of leakage current across fabricated Schottky diodes have been detected as compared to the available commercial diodes. The Landauer transport model found to be excellent fitting for understanding the electron transport mechanism for these fabricated diodes. The Fermi energy level pinned near effective gap center that shifts under the bias condition due to the metal induced gap states. The Schottky diodes as a bypass in solar cell panel demonstrates the significant enhancement in photo-response and efficiency of solar cell in the presence of sunlight.