SYNTHESIS AND CHARACTERIZATION OF La-DOPED ZnO (La:ZnO) FILMS FOR PHOTODETECTORS

Abstract

In this work, the La-doped ZnO thin films were fabricated with different La concentrations by the use of sol–gel technique to synthesize the photodevice. The transparent metal oxide La-doped ZnO thin films were grown on glass and [Formula: see text]-Si substrates using spin coating technique. Optical, surface morphology and electrical characterization of the fabricated Al/[Formula: see text]-Si/La:ZnO/Al devices have been performed using [Formula: see text]–[Formula: see text] and [Formula: see text]/[Formula: see text]–[Formula: see text] characteristics under dark and different illumination conditions. Herein, from [Formula: see text]–[Formula: see text] characteristics, the crucial electronic parameters such as barrier height, ideality factor and series resistance were investigated. The photodevice transient photocurrent increases with the increase of illumination intensity. The current ratios of [Formula: see text]/[Formula: see text] were calculated for the fabricated devices. Among the devices, the highest photoresponse was found to be about 2186 for the Al/[Formula: see text]-Si/La(0.5 wt.%):ZnO/Al structure. The [Formula: see text]–[Formula: see text] behavior of fabricated device confirms the presence of interface states. The obtained results and photoresponse behaviors suggested that Al/[Formula: see text]-Si/La:ZnO/Al devices can enhance the applications in optoelectronic devices such as photodetectors.

The Optoelectrical Properties of Li: TiO2/p‐Si Photodiodes for Various Li Doping

“…This indicates the presence of interfacial charges in the heterostructure but does not contribute to the capacitance due to their inability to follow the alternating current (AC) signal at high frequency. [76,77] In addition, some researchers studying on negative capacitance reported that the negative capacitance observed at high frequency could be attributed to the inductive effect caused by the injection of high levels of minority carriers into the semiconductor. [63,78] The G-V graphs of undoped and Li-doped TiO 2 diodes in the frequency range of 10-500 kHz are shown in Figure 13a-d.…”

“…When frequency increases, the conductance of diodes increases due to series resistance and the states of the interface. [76,77] The series resistance of a diode is an important parameter as it affects the capacitance and conductance of diodes. Figure 14a-d demonstrates the variation of R s versus V at the various frequencies for different Li doping.…”

Effect of Lanthanum Doping on the Structural, Morphological, and Optical Properties of Spray-Coated ZnO Thin Films

“…The transparent conducting oxide (TCO) semiconductors are of great interest due to their better optical and electrical properties. Currently, a lot of research works are looking at TCO semiconductor material-based photodetectors [1], UV sensors [2], optical limiters [3], and solar cells [4]. The ZnO, ZnS, CdO, and CdS materials of the II-VI semiconducting groups are good examples of TCO materials.…”