Heterojunction Amorphous Silicon Solar Cells with n-Type Microcrystalline Cubic Silicon Carbide as a Window Layer

Abstract

The application of phosphorus doped hydrogenated microcrystalline cubic silicon carbide (µc-3C–SiC:H) as a window layer of amorphous silicon (a-Si:H) solar cells is demonstrated. The µc-3C–SiC:H thin films were deposited by hot-wire chemical vapor deposition technique using monomethylsilane gas diluted with hydrogen. The deposition of µc-3C–SiC:H on a transparent conducting electrode (TCO) was realized by the use of titanium dioxide (TiO2) covered on the TCO. Using this covering technique, the µc-3C–SiC:H was applied to the n-layer of an n–i–p-type a-Si:H solar cell. An efficiency of 4.61% with an open circuit voltage of 0.947 V was obtained. This result indicated that the use of µc-3C–SiC:H for an n-layer will realize to achieve a higher Voc in the photovoltaic characteristic.

Preparations of P‐ and N‐doped hydrogenated microcrystalline cubic silicon carbide films by VHF plasma enhanced chemical vapor deposition method for Si thin film solar cells

“…On the other hand, the dark conductivity of P-doped materials prepared by HWCVD method is 10 -2 -10 -1 S/cm [1,3]. These values seem to be high enough for a doping layer.…”

“…One of the most promising materials is hydrogenated microcrystalline cubic silicon carbide (μc-3C-SiC:H) films [1,3]. This material possesses a bandgap energy of 2.2 eV [1,3] and has been expected to have higher carrier mobilities compared with those of amorphous counterpart. Thus, a Si thin film solar cell with higher energy conversion efficiency and a higher open circuit voltage will be realized when utilizing high quality μc-3C-SiC:H film as a doping layer.…”

“…For preparing n-type μc-3C-SiC:H films for Si thin film solar cells, nitrogen (N) [1,4] and phosphorus (P) [1,3] are usually employed as dopant materials [5,6]. It has been reported that the dark conductivity of N-doped μc-3C-SiC:H films at room temperature prepared by hot-wire chemical vapor deposition (HWCVD) method are 10…”

“…In this study, we have tried to prepare n-type μc-3C-SiC:H films [1,3] by doping N and P by VHF [7] plasma enhanced chemical vapor deposition (PECVD) method. We use ammonia (NH 3 ) for one of the source materials for n-type dopants.…”

“…Nitrogen (N) and phosphorus (P) doped n-type hydrogenated microcrystalline cubic silicon carbide (μc-3C-SiC:H) films have been prepared by VHF plasma enhanced chemical vapor deposition method for Si thin film solar cells. Ammonia (NH 3 ) is employed as a N source. We show that the dark conductivity of the film reaches a value of about 10 -2 S/cm by doping N and P for a doping ratio of 0.8 %.…”