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The thermally deposited indium-tin-oxide (ITO) film on single-junction GaAs solar-cell as an excellent antireflection, passivation and window layer to achieve higher efficiency is demonstrated. The passivated characteristic of the ITO-film on GaAs solar-cell is examined by saturation-current and ideality factor. The antireflection of the ITO-film on GaAs solar-cell is revealed by optical-reflectance and external quantum-efficiency. The efficiency of 23.52% for the GaAs cell with ITO antireflection-coating (ARC) was higher than that of 21.92% for the GaAs cell with SiO 2 ARC.

In this study, light trapping of textured silicon solar cell based on light scattering and angle of incident light of plasmonics indium nanoparticles (In NPs) of various dimensions is demonstrated. The light trapping modes of textured surface with and without In NPs for incident angles of 0°, 35.3°, and 54.7° are proposed and characterized. The optical reflectance, external quantum efficiency and photovoltaic performance depended on the dimensions of plasmonics In NPs and angles of incident light are measured and compared.

This study presents high-efficiency of 23.52% single-junction GaAs solar cell using ITO-film as antireflection and passivation layer deposited by thermally-RF-sputtering. The impressive enhanced in efficiency of 8.94% was obtained, compared to the cell with SiO 2 -film.

GaAs-based multi-junction solar cells (MJ-SCs) provide a wide solar-energy absorption-band (300–1800 nm), but designing and fabricating a broadband antireflection coating (ARC) are challenging. Because MJ-SCs are typically in a series that connects each subcell, the total output current is limited by the subcell that generates the smallest photocurrent. Thus, the ARC for MJ-SCs must be designed not only to obtain broadband absorption but also to minimize light reflection at the wavelength band of the current-limited cell. This study proposes a broadband SiO 2 /graded-index TiO 2 ARC for improving the current-limited subcell performance by using a hybrid deposition (e-beam evaporation and spin-on coating). A bottom TiO 2 layer and a top SiO 2 layer were deposited through e-beam evaporation, but the middle TiO 2 layer was deposited using spin-on coating because the refractive index values of the TiO 2 films could be tuned by applying the spin speed. Therefore, the graded-index TiO 2 layers were easily obtained using a hybrid deposition method. In addition, a suitable reflectance spectrum of an ARC structure for a middle-cell current-limited triple-junction (3-J) GaAs solar cell was simulated using commercial optical software. The photovoltaic current–voltage and external quantum efficiency (EQE) were measured and compared. The resulting improvements of a short-circuit current of 32.4% and conversion efficiency of 31.8% were attributed to an enhanced EQE of 32.97% as well as a low broadband reflectance exhibited on the middle cell of the 3-J GaAs solar cell with a SiO 2 /graded-index TiO 2 ARC.

In this paper, we propose and demonstrate a novel technique on improving the conversion efficiency for a metal-insulator-semiconductor (MIS) transistor-based solar cell by using a voltage biasing transparent electrode. The device structure is consisted of a Si-solar cell, a SiO 2 oxide layer, an indium tin oxide (ITO) transparent electrode, and two ohmic-contact electrodes for n-Si and p-Si. The used ITO transparent electrode with a high transmittance at the visible wavelengths and a low sheet resistance are obtained by a sputtering system. The performances of the bare Si-solar cell, the cell with ITO/SiO 2 layers, and the cell with ITO/SiO 2 layers and ITO electrode applying a bias voltage are sequentially characterized under AM1.5 solar illumination. Comparing the performance with the bare solar cell, the efficiency of the solar cell with ITO/SiO 2 films was enhanced of 34.3%. In which, the thin ITO/SiO 2 films provide a function like an anti-reflection (AR) coating. Furthermore, the efficiency as a function of bias-voltage was also observed when the ITO transparent electrode was biased at different volts. At 5 V biasing, the efficiency increasing of more 25.7% was obtained in our recently results, which compared the cell with zero volt biasing. The operation mechanism of the biasing dependent is also discussed.

This study examines using sub-wavelength surface structure (SWS) anti-reflection (AR) coating with a broad wavelength range of low reflectance and wide-acceptance angles of incident light fabricated on solar cells for improving solar cell performance. The SWS AR coating consisted of TiO 2 and SiO 2 layers that had thicknesses of a quarter-wavelength and heights of 300-nm SiO 2 nano-pillars on the top surface of the sub-wavelength structure. The sub-wavelength SiO 2 nano-pillars were formed using a reactive ion etching process with CF 4 that involved using silver nanoparticles as the etching masks. The reflective spectrum of the SWS AR coating was examined using software simulation and experimental measurement. The average reduced reflectance of SWS AR coating was less than 3% between 450 nm and 900 nm wavelengths. SWS AR coating improved solar cell performance in conversion efficiency and maximal output power (P MAX ) at higher incident angle illumination. Therefore, at an incident angle of 60°, the conversion efficiency improvement was 52.9% and the P MAX was 55.8%, as compared with the cells that had two layers (TiO 2 /SiO 2 ) of AR coating.

In this study, we sought to improve the light trapping of textured silicon solar cells using the plasmonic light scattering of indium nanoparticles (In NPs) of various dimensions. The light trapping modes of textured-silicon surfaces with and without In NPs were investigated at an angle of incidence (AOI) ranging from 0° to 75°. The optical reflectance, external quantum efficiency (EQE), and photovoltaic performance were first characterized under an AOI of 0°. We then compared the EQE and photovoltaic current density-voltage (J-V) as a function of AOI in textured silicon solar cells with and without In NPs. We observed a reduction in optical reflectance and an increase in EQE when the cells textured with pyramidal structures were coated with In NPs. We also observed an impressive increase in the average weighted external quantum efficiency (∆EQEw) and short-circuit current-density (∆Jsc) in cells with In NPs when illuminated under a higher AOI. The ∆EQEw values of cells with In NPs were 0.37% higher than those without In NPs under an AOI of 0°, and 3.48% higher under an AOI of 75°. The ∆Jsc values of cells with In NPs were 0.50% higher than those without In NPs under an AOI of 0°, and 4.57% higher under an AOI of 75°. The application of In NPs clearly improved the light trapping effects. This can be attributed to the effects of plasmonic light-scattering over the entire wavelength range as well as an expanded angle of incident light.

The current matching of the middle-cell current-limited triple-junction GaAs/Ge solar-cells after-epitaxial-growth was improved using the matrix-profile TiO2 layer and indium-nanoparticles plasmonics. The optical reflectance, short-circuit current, conversion efficiency and external quantum efficiency are used to characterize the effects of the matrix-profile TiO2 layer and indium-nanoparticles plasmonics on the performances of solar cells. The cell with indium-nanoparticles deposited on the combined layers of a 10-nm-thick TiO2 and a 30-nm-thick TiO2 of 60% coverage shown the improving of current matching in middle-cell that increasing in conversion efficiency by 8.36% and short-circuit current of 12.91% are obtained, compared to the bare solar cells.

We demonstrate the enhanced performances of Si-solar-cells using the spin-on-film device-processes and Indium-nanoparticle plasmonics. The short-circuit-current of the cell with indium-nanoparticles-plasmonics increase by 56.03% (from 3.48 to 5.43 mA) is obtained, compared to the bare-solar-cell.

This paper demonstrate experimentally the top-cell external quantum efficiency (EQE) improving of the triple-junction GaAs-based solar cell using a SiO2-nanopillars/SiO2/TiO2 graded-index anti-reflection coating (GI-ARC). The reflectance and EQE of the solar cells with SiO2/TiO2 double-layer ARC and with SiO2-nanopillars/SiO2/TiO2 GI-ARC are measured and compared. The reflectance of cell with SiO2-nanopillar/SiO2/TiO2 GI-ARC had most favorable low reflectance between 550-700 nm wavelengths. Therefore, the EQE enhancement of 5.88% on top-cell and -1.56% on middle-cell and the best current matching were achieved.

We demonstrate experimentally the improvement of the external quantum efficiency (EQE) and current-matching of the triple-junction GaAs-based solar cell using periodic-patterns incorporated with random nano-sized indium-nanoparticles plasmonics. The average EQE decreased of -9.8% in top-cell and increased of +2.4% in middle-cell were obtained as the solar cell with periodic-patterns random nano-size indium-nanoparticles. Thus, photocurrent generated in the current-limited middle-cell was improved of ~3.4% and the conversion-efficiency was enhanced of ~3.0%, which current matching was also achieved under 1-sun AM1.5G illumination.

We demonstrate MOS-structure silicon solar-cells using a biasing antireflective-ITO-electrode to enhance the photovoltaic performance. The enhancement of the short-circuit-current and conversion-efficiency was confirmed by the light-current-voltage and induced-junction-capacitance measurements when applied 0-2.5 V-biasing on ITO-electrode.

The reflective spectrum and the incident angle effects of double-layers AR-coating and Sub-Wavelength AR-coating on the triple-junction GaAs Solar Cell are characterized by short-circuit current (I sc ), open-circuit voltage (V oc ), and conversion efficiency (η).

We demonstrate a novel concept for a MOS-structure Si photovoltaic device with an increasing in photocurrent of 12.93% based on a biasing source applied to the MOS transparent ITO-gate-electrode using an auxiliary biasing solar cell.

We report the performance enhancement of GaAs-based triple-junction solar cells using novel indium nanoparticles upon the cell front-surface to achieve the top cell current matching. The external quantum efficiency (EQE) enhancements of > 5% in top cell at wavelengths from 350 nm to 450 nm are achieved as the cell with indium nanoparticles plasmonic structure. Besides increasing in short circuit current (I SC ) of 11.20% (from 2.95 mA to 3.28 mA) and in conversion efficiency (η) of 13.5%(from 20.8% to 23.6%) are also obtained under one sun AM1.5G illumination.

Single-photon performances characterization of InGaAs/InP avalanche photodiodes (APDs) using a dual-APDs balanced-capacitance self-differencing operation was proposed. Small spike-noise and low discrimination-level were simultaneously achieved. Reducing in dark-count rate was also presented in the proposed scheme.

We report the fabrication and performance characterization of 1550 nm separate absorption, grading, charge, and InP/InAlAs hetro-multiplication avalanche photodiodes (SAGCHM APDs) for single photon detection applications. The linear mode performance of the fabricated APDs are firstly characterized that the dark current at 95% of the breakdown voltage was 30 pA and 15 nA at 200K and 300K, respectively. The gain-bandwidth product of 62 GHz was obtained at room temperature. For single photons detection characterization, however, our APD was operated in the gated passive quenching mode, at lower temperature and incorporated with an optimizing spike-cancellation self-differencing circuit. Under the temperature of -50°C and the gate repetition frequency of 100 KHz with pulse width of 2 ns, the lowest dark count probability (P dc ) of 1.2 x 10 -5 , the highest single-photon detection efficiency (η det ) of 22.5%, and the lowest noise equivalent power (NEP) of 1.5x10 -15 W/(Hz) 1/2 were obtained, respectively. Moreover, we demonstrated the transmission distance as a function of quantum bit error rate (QBER) based on the obtained performance parameters. The maximum transmission distance, at QBER=15%, of 43 km was achieved.

In this study, the enhanced performance of a triple-junction GaAs-based solar cell using a SiO 2 -nanopillar/SiO 2 /TiO 2 graded-index antireflection coating (GI-ARC) was demonstrated. The optical reflectance, photovoltaic current-voltage (I-V), and external quantum efficiency (EQE) of a cell with a SiO 2 /TiO 2 double-layer (DL) ARC and a cell with a GI-ARC were measured and compared. The cell with a GI-ARC exhibited the lowest optical reflectance. Thus, the average EQE enhancements (ΔEQE) of the cell with a GI-ARC compared to the cell with a DL-ARC were 5.88% for the top cell and –1.56% for the middle cell. In addition, a small difference in the photocurrent generated between the top cell and the middle cell was achieved. Finally, an additional 0.52% increase (from 24.99% to 25.51%) in conversion efficiency was obtained.