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The study examines the optical and electrical characteristics of n-ZnO:Al (AZO) thin films that were deposited on p-Si using the sol-gel dip-coating process, with thicknesses ranging from three to six cycles. The I-V characteristics of the diode device exhibited a high and low current under forward and reverse bias, respectively. The ideality factors were found to decrease from 2.78 to 2.13 with an increase in the number of layers from 3C to 6C. However, it was revealed that the barrier height increased from 0.72 to 0.79 eV. Similarly, the rectification ratio increased from 3196 at ±4 V to 5253 at ±4 V with an increase in the thickness of the emitter layer. Some diode parameters were calculated according to the thermionic and Chueng models and found to be in a range comparable to the literature. The optical study based on photoluminescence under UV excitation showed typical emission spectra of n-AZO/-Si heterostructure characterized by a high emission band around 389 nm, which is due to the recombination of excitons (e-=h+). The various intrinsic defects present in ZnO-doped Al thin films are attributed to the broad emission band in the visible range. The chromaticity study with color properties indicated that the correlated color temperature value of the sample 3C (1380 K) falls in the warm white light region. However, the correlated color temperature value of sample 6C (4454 K) is located in the cool white light source region, which is more suitable as an LED lighting source. It was found that by increasing the emitter layer thickness, the correlated color temperature value of the 6C sample is getting closer to 6504 K - the Commission Internationale de l'Eclairage (CIE) standard for daylight (D65). However, unlike the Duv value of the 6C sample (0.011), the one of the 3C sample (0.0032) is located within the acceptable shift range (±0:006). Based on this study, these heterostructures might be an appealing option for manufacturing W-LEDs with n-UV/blue LED chips as the excitation source for use in displays and lighting. [ABSTRACT FROM AUTHOR]

In this paper, the electrical properties different diodes were reported. Pure and Al-doped ZnO thin films of different concentrations (Al: 1, 2 and 3 wt.%) were deposited by sol-gel dip-coating onto p-Si substrate to form heterojunctions. Zinc acetate dehydrate, Hexahydrate aluminum chloride, ethanol and ethanolamine were used as a starting material, doping, solvent and stabilizer, respectively. The dip-coating process with drying was repeated 6 times to obtain multilayer films. The morphological and electrical properties of the thin films as a function of Al concentration have been investigated using atomic force microscopy (AFM) and current-voltage (I-V) measurements at room temperature. AFM images revealed that grain sizes and surface roughness increase with increasing Al concentration. I-V characteristics of the diodes exhibited high and low currents under forward and reverse bias, respectively. The ideality factors (n), rectification ratio (RR) and barrier heights (BH) were found to range from 1.97 to 8.34, 0.84 to 5958 and 0.80 to 0.86 eV for different Al doping concentrations, respectively. These findings showed no monotonic behaviour of the calculated parameters with varying Al doping concentrations. The best electrical characteristic was obtained for the sample n-ZnO: 2 % Al/p-Si, with an ideality factor of 1.97 eV, reverse saturation current of 1.69 ± 10– 8 A, rectification ratio of 5958 at ± 2 V, and barrier height of 0.85 eV. [ABSTRACT FROM AUTHOR]