Inductively coupled plasma grown semiconductor films for low cost solar cells with improved light-soaking stability

Abstract

We investigate the performance of a single-junction amorphous Si (a-Si) solar cell fabricated with inductively coupled plasma (ICP) deposition technique. The high-density plasma resulting from high dissociation capacity of ICP enables good-quality hydrogenated Si films to be synthesized at low temperatures. High-density ICP also promotes the diffusion of reactive radicals on substrates and forms a-Si:H films with low defect density (∼3 × 1015 cm−3). We demonstrate single-junction a-Si solar cells with a conversion efficiency of 9.6% and improved light-soaking stability. This low thermal-budget thin-film technique could open up the feasibility of efficient thin film solar cells on flexible substrates.

Multi-functional stacked light-trapping structure for stabilizing and boosting solar-electricity efficiency of hydrogenated amorphous silicon solar cells

“…According to our previous study, the ICP intrinsic a-Si:H layer has a low-defect density of 3 Â 10 15 cm À3 . 15,19 The MS-PV shows a high J sc of 16.3 mA/cm 2 with the conversion efficiency as high as 9.6%. In addition, the device has a low dark saturation current of 1.2 Â 10 À9 A/cm 2 and a high FF of 70.4%.…”

“…14 The low plasma power density for the a-Si:H deposition can also minimize the ion bombardment on the substrate. 15 Moreover, the nano-scale smooth surface of the TCO electrode by smoothening the protrusion and sharp valley of FTO/Au-NPs is beneficial to the growth of the dense a-Si:H film of low-defect density. 16 The Au-NPs/AZO layer enhances the absorption of the green-red solar energy via the plasmonic effect, and the micro-structured FTO functions like a short-wavelength scatter, which increases the ultraviolet-blue solar-energy utilizaiton.…”

“…First Au-NPs were self-assembled on the micro-structured Asahitype substrate (SnO 2 :F, FTO), followed by the deposition of an ultra-thin AZO capping layer. The a-Si:H p-i-n multilayer (12-nm p-layer/400-nm i-layer/20-nm n-layer) was then deposited on the light-trapping electrode by high-density inductively coupled plasma CVD (ICP-CVD), 15 which can produce a-Si:H thin-films of low defect at the substrate temperature of 140 C. A 80-nm-thick indium tin oxide (ITO) and a 500-nm-thick Al metal were then deposited on the ICP a-Si:H p-i-n multilayer as the back-electrode. The monodispersed Au-NPs of 15 nm in size in water solution were synthesized by the citrate chemical reduction method at low temperatures.…”

“…The device reached accordingly a steady-state temperature at 60 C due to the irradiation, thereby accelerating photodegradation of the device. 15 The defect density of the intrinsic a-Si:H layer on different electrodes was determined by the drive-level capacitance profiling (DLCP). 18,19 Table I lists the photovoltaic characteristics of the three light-trapping-structured solar cells.…”

High‐Density Plasma‐Enhanced Chemical Vapor Deposition of Si‐Based Materials for Solar Cell Applications

“…Li et al [25] used the built-in one-turn coil inductance antenna driven by 13.56 MHz RF power to fabricate μc-Si:H with tunable preferred orientation through controlling the hydrogen dilution. By the similar method with external conductance coil power by the same frequency generator, Shen et al [26,27] obtained low defect density ((3 x 10 15 /cm 3 ) a-Si:H films, from which a single-junction a-Si:H solar cell with energy conversion efficiency of 9.6% was successfully fabricated. The researchers from Hiroshima University realized the high-rate deposition (up to 4 nm/s) of μc-Si:H with a low-level defect density in the year of 2001 [28,29].…”