Kazuhiro Gotoh

We studied the effect of deposition temperature on the hydrogen distribution and the passivation performance of hydrogenated amorphous silicon (a-Si:H) coated crystalline silicon (c-Si) heterojunctions as a model of high efficiency solar cell structures. Nuclear reaction analysis (NRA) was employed to obtain hydrogen depth profiles of the heterojunctions prepared at temperatures from 80 to 180 °C. The implied open circuit voltage (i-VOC) and carrier lifetime monotonically increased with increasi

This study describes the fabrication of silicon nanocrystals (Si NCs) in silicon oxide layers, which led to high-performance passivation and enhanced carrier transport in crystalline silicon (c-Si) solar cells. These Si NCs comprised nanocrystalline transport pathways in ultrathin dielectrics for reinforced passivating contact structures (NAnocrystalline Transport path in Ultrathin dielectrics for Reinforcing (NATURE) contacts). Si NCs were formed in silicon oxide layers by depositing hydrogenat

We studied on surface morphology, optical properties and passivation performance of copper iodide (CuI) on crystalline silicon (c-Si) deposited by spin-coating for application to hole-selective contacts to realize high performance and low-cost c-Si solar cells. Absorbance was increased by depositing CuI on c-Si owing to absorption and antireflection effect of CuI. From surface images by scanning electron microscope measurements, discontinuous layer was observed for CuI deposited Si. Effective li

We report on the effect of sputtering deposition of indium tin oxide (ITO) as the transparent conductive oxide layer on the passivation performance of hydrogenated amorphous silicon/crystalline silicon heterojunctions. The influence of sputtering damage on passivation performance is studied by varying the ITO layer thickness from 0 nm to 80 nm. The passivation performance decreases considerably up to 10 nm and increases gradually from 20 nm to 80 nm, indicating that damage and recovery stages ar

The impact of the implementation of magnesium interlayer and the layer thickness ( t TiO x ) of titanium oxide on the electrical properties of TiO x /SiO y /Si heterojunctions is investigated to improve electron transport for use in silicon heterojunction solar cells. The passivation performance is improved with increasing t TiO x . For the samples with Mg interlayer, ohmic contact can be attained for the thicker TiO x layer compared with the sample without Mg interlayer. Schottky contact is mit

Carrier‐selective contacts prepared by atomic layer deposition (ALD) have received significant attention for developing high‐efficiency solar cells. Herein, the electrical properties of titanium oxide (TiO x ) prepared by ALD are manipulated by modulating the deposition temperature during ALD. Tunable electrical properties are possible due to the existence of oxygen vacancies in TiO x prepared at low deposition temperatures. TiO x layers prepared at 100 and 150 °C provide a low contact resistivi

Abstract Variable-angle spectroscopic ellipsometry analysis is performed to study the impact of post-deposition annealing on the passivation performance of the heterocontacts consisting of titanium oxide and silicon oxide on crystalline silicon (c-Si) prepared by atomic layer deposition (ALD) for the development of high-performance ALD-TiO x /SiO y /c-Si heterocontacts. The highest lifetime of 1.8 ms is obtained for the TiO x /SiO y /c-Si heterocontacts grown at 175 °C after annealing at 275 °C

We report on our attempt to increase the carrier density in the p-type polycrystalline silicon (poly-Si) layers grown by aluminum-induced crystallization (AIC) employing a B-doped Si target. Hall measurement revealed that we could obtain a lower-resistance and heavily doped p-type continuous poly-Si thin layer formed by AIC using B-doped a-Si. According to our evaluation of tunnel oxide passivated contact (TOPCon) solar cells with AIC-grown poly-Si, the AIC-TOPCon solar cells fabricated at 570 °