Microcrystalline series photovoltaic element and process for fabrication of same

A photovoltaic element having a stacked structure comprising a first semiconductor layer containing no crystalline phase, a second semiconductor layer containing approximately spherical microcrystalline phases, and a third semiconductor layer containing pillar microcrystalline phases which are stacked in this order, wherein said third semiconductor layer has a layer region containing approximately spherical microcrystalline phases mingled together with said pillar microcrystalline phases in the vicinity of said second semiconductor layer.

A process for producing a photovoltaic element, comprising the steps of:

• (a) forming a first semiconductor layer containing no crystalline phase on a substrate,
• (b) forming a second semiconductor layer containing approximately spherical microcrystalline phases on said first semiconductor layer, and
• (c) forming a third semiconductor layer containing pillar microcrystalline phases on said second semiconductor layer, wherein in the course of forming said second semiconductor layer in the step (b), a dilution ratio of a film-forming raw material by a hydrogen gas is increased to form said spherical microcrystalline phases contained in said second semiconductor layer such that said spherical microcrystalline phases situated on the side of said third semiconductor layer have an average size which is greater than that of said spherical microcrystalline phases situated on the side of said first semiconductor layer.

A process for producing a photovoltaic element, comprising the steps of:

• (a) forming a first semiconductor layer containing no crystalline phase on a substrate,
• (b) forming a second semiconductor layer containing approximately spherical microcrystalline phases on said first semiconductor layer, and
• (c) forming a third semiconductor layer containing pillar microcrystalline phases on said second semiconductor layer, wherein in the course of forming said second semiconductor layer in the step (b), a temperature of forming said second semiconductor layer is increased to form said spherical microcrystalline phases contained in said second semiconductor layer such that said spherical microcrystalline phases situated on the side of said third semiconductor layer have an average size which is greater than that of said spherical microcrystalline phases situated on the side of said first semiconductor layer.

A photovoltaic element comprising at least a first transparent electrically conductive layer formed on a substrate, a silicon series semiconductor layer having at least one p-i-n junction stacked on said first transparent electrically conductive layer, and a second transparent electrically conductive layer stacked on said silicon series semiconductor layer, characterized in that said silicon series semiconductor layer has a p-i-n junction structure which comprises a primary layer comprising an amorphous semiconductor layer having a first conduction type and a crystalline phase-containing semiconductor layer having a first conduction type sequentially stacked, a crystalline phase-containing i-type semiconductor layer, and a non-single crystal semiconductor layer having a second conduction type which are sequentially stacked, wherein said crystalline phase-containing semiconductor layer of said primary layer contains crystalline phases such that their size magnitude is increased toward said crystalline phase-containing i-type semiconductor layer.

A process for producing a photovoltaic element having at least a first transparent electrically conductive layer formed on a substrate, a silicon series semiconductor layer having at least one p-i-n junction stacked on said first transparent electrically conductive layer, and a second transparent electrically conductive layer stacked on said silicon series semiconductor layer, characterized in that said silicon series semiconductor layer is formed by a method comprising the steps of:

• (a) forming a primary layer by sequentially forming an amorphous semiconductor layer having a first conduction type and a crystalline phase-containing semiconductor layer having a first conduction type, and
• (b) sequentially forming a crystalline phase-containing i-type semiconductor layer and a non-single crystal semiconductor layer having a second conduction type on said primary layer,
• wherein in said step (a), said crystalline phase-containing semiconductor layer having a first conduction type is formed to contain crystalline phases such that their size magnitude is increased toward said crystalline phase-containing i-type semiconductor layer.