Current Enhancement of Aluminum Doped ZnO/<I>n</I>-Si Isotype Heterojunction Solar Cells by Embedding Silver Nanoparticles

Abstract

To improve Plasmonic energy harvesting, the Al doped ZnO (AZO) and Si heterojunction was studied for plasmonic photovoltaic applications. Silver nanoparticles (Ag NPs) were embedded in AZO, resulting in direct energy absoption from Ag NPs, positioned close to the junction. This structure has a benefit of avoiding highly doped lossy layers of conventional solar cell structures. Al doped ZnO (AZO) was deposited on n-Si substrate by dual beam sputtering method to fabricate AZO/Si heterojunction solar cells. AZO provides a transparent current spreading effect and rectifying junction with n type silicon (Si). Silver nanoparticles (Ag NPs) were embedded in AZO film (240-270 nm thick) with a sandwich-like structure. The position of Ag NPs in the AZO film was controlled to be located at 10, 20 and 40 nm distance from the Si absorber layer. Fabricated solar cells show improved performance in terms of the short circuit current (J(sc)) and the quantum efficiency (QE). Finite difference time domain (FDTD) simulations were carried out to investigate the QE enhancement and optimize photocurrent gain under an AM1.5G solar spectrum. In calculation, absorption enhancement is maximized when Ag NPs are located close to the Si layer in the range of 10-40 nm. Experimentally, 20 nm distance of Ag NPs from the Si showed the best performance with 0.36 V of open circuit voltage (V(oc)), 28.3 mA/cm2 of J(sc) and 5.91% of coversion efficiency. The QE showed 15% of enhancement around lambda = 435 nm and 5-10% of enhancement within lambda = 600-1000 nm.

High-Quality ITO/Al-ZnO/n-Si Heterostructures with Junction Engineering for Improved Photovoltaic Performance

“…The device current transport mechanism was mainly determined by using the AZO/Si heterojunction, which provided the active junction built-in potential (qV bi ) for the photogenerated carrier separation under the illumination [37,38]. The theoretical AZO/n-Si junction band diagram before and after equilibrium conditions are shown in Figure 2c [36,37]. To better understand the ITO/AZO/Si structure properties, the chemical composition depth profiles of ITO/AZO/Si structures were characterized via a secondary ion mass spectrometer (SIMS).…”

DISPERSION IN IMPEDANCE SPECTRA OF ISOTYPE CdO–ZnO THIN FILM HETEROSTRUCTURE ON APPLIED DC BIAS

“…Only few reports are available exploring the physics of such isotype heterojunction. [12][13][14][15] Recently, preparations of CdO-ZnO composite¯lm employing SILAR method and its LPG gas sensing properties have been reported by Nwanya et al 16 Synthesis of CdO-ZnO composite prepared by microwave assisted method and its antibacterial activity against human pathogens have also been reported. 17 In one of our previous article, 18 some fundamental investigations and results on CdO-ZnO isotype heterostructure were reported.…”

Influence of the Thickness and Doping Concentration in p- and n-Type Poly-Si Layers on the Efficiency of a Solar Cell Based on a Carbon Fiber

“…In this study, the effects of the thickness and doping concentration in p-and n-type poly-Si layers on the efficiency of a solar cell based on a carbon fiber were theoretically analyzed by utilizing a finite-difference time-domain (FDTD) algorithm [11,12]. The solar cell efficiency (η ) based on the carbon fiber gradually increased and finally saturated with increasing thickness of the p-type poly-Si layer because of the dependence of the light harvesting efficiency (ηlh) on the absorbed light intensity (Iabs), corresponding to the thickness of the p-type poly-Si layer (tp).…”