Semi-transparent Si-rich SixC1−x p–i–n photovoltaic solar cell grown by hydrogen-free PECVD

Abstract

A semi-transparent silicon-rich (Si-rich) silicon carbide (Si x C 1Àx ) based thin-film p-i-n junction photovoltaic solar cell is demonstrated, which is synthesized by hydrogen-free plasma enhanced chemical vapor deposition (PECVD) with the conversion efficiency optimized by detuning plasma power and intrinsic layer thickness. The hydrogen-free PECVD process effectively decelerates the decomposition of hydrogen from the Si-rich Si x C 1Àx films so as to facilitate the passivation of surface dangling bonds. When synthesizing at a fluence ratio of R ¼film is greatly red-shifted to 1.54 eV due to the enhancement of Si content. By reducing the RF plasma power to 20 W, the Si-rich Si x C 1Àx enlarges its above-bandgap (l¼ 0.4-0.8 mm) optical absorption up to 10 4 -10 5 cm À1 , which is even one order of magnitude larger than that of bulk crystalline Si. The incomplete dissociation of CH 4 and SiH 4 under low-power PECVD growth also helps to suppress the defects and improve the electrical properties of Si-rich Si x C 1Àx . By doping with the PH 3 and B 2 H 6 fluence ratios of 5.8% and 2.1%, the resistivities of n-type and p-type Si-rich Si x C 1Àx films are decreased to 0.87 and 0.12 U cm, respectively. Thinning the intrinsic Si-rich Si x C 1Àx layer to 25 nm further promotes the conversion efficiency of the Si-rich Si x C 1Àx based p-i-n photovoltaic solar cell.After annealing at 650 C, the open-circuit voltage (V oc ) and short-circuit photocurrent density (J sc ) of the annealed Si-rich Si x C 1Àx and amorphous Si based dual-junction thin-film photovoltaic solar cell are increased to 0.78 V and 19.1 mA cm À2 , respectively, leading to a filling factor of 35% and a conversion efficiency of up to 5.24%.

Strong optical nonlinearity of the nonstoichiometric silicon carbide

“…8 Cheng et al optimized the i-Si x C 1Àx thickness to 25 nm in Si-rich Si x C 1Àx -based solar cells for enhancing the filling factor and conversion efficiency to 0.25 and 1.7%, respectively. 9 Estrada et al 10 demonstrated Si x C 1Àx based thin-film transistors with a field-effect mobility of up to 1.9 Â 10 À2 cm 2 V À1 s À1 . Furthermore, Si x C 1Àx has been employed in high-temperature and highpower electronics for maintaining device sensitivity and stability under extreme environments because of its superior thermal stability and chemical inertness.…”

Nonstoichiometric SiC Bus/Ring Waveguide Based All-Optical Data Format Follower and Inverter

“…From this point of view, the nonstoichiometric silicon carbide (SiC) is recently considered as one of the potential candidates. The nonstoichiometric SiC has been extensively investigated for different applications such as light-emitting diodes (LEDs), − solar cells, − and detectors. − Benefiting from the relatively wide bandgap energy ( E g , for the commonly encountered polymorph of a-SiC E g = 3.05 eV) and high thermal stability, the nonstoichiometric SiC offers a low absorption coefficient and a high optical damage threshold, which is suitable for high-power operation. Moreover, the nonstoichiometric SiC is predicted to exhibit high nonlinear refractive index at optical telecommunication wavelengths; however, there is lack of literature discussing the transient variation on the nonlinear refractive index of nonstoichiometric SiC at near-infrared wavelengths …”

Advanced Development of Sustainable PECVD Semitransparent Photovoltaics: A Review

“…Recently, a group of scientists developed a semitransparent non-stoichiometric photovoltaic solar cell based on Si-rich Si x C 1-x p-i-n grown by hydrogen-free PECVD at low plasma power (Cheng et al, 2014). During the fabrication process using RF plasma power ranging from 20-100 W (40W step) at a power density of 560 mW cm −2 , the optical bandgap of Sirich Si x C 1-x absorbing layer was effectively controlled by varying the Si/C ratio.…”

“…Furthermore, the charge collection process was realized using ITO and Al electrode which were connected to P-type SiC and N-type SiC films respectively (see Figure 7). Ultimately, the optimized device fabricated with an absorbing layer of 25 nm exhibited the highest power conversion efficiency (Cheng et al, 2014). The optimization of deposition parameters remains a key challenge for better performance of the devices (see table 2).…”

“…STPSCs have been recently manufactured via thin films' deposition techniques such as Inkjet printing, Pulsed laser deposition (PLD), and PECVD as reported in recent studies. This includes perovskite solar cells which reached a record high efficiency of over 25% (Cheng et al, 2014;Xie et al, 2018;Corzo et al, 2020;Lim et al, 2021b). In addition, recent studies have demonstrated that the use of various protective and antireflective coatings, such as intrinsic a-Si:H layers, among others, can considerably enhance the performance of future generations of thin film solar cells (Uzum et al, 2017;Zhao et al, 2017;Li et al, 2020a;Bacal et al, 2020;Qu et al, 2021).…”