High quality photovoltaic semiconductor material and laser ablation method of fabrication same

Patent · Tue Jul 27 00:00:00 EDT 1993

OSTI ID:6319366

Ovshinsky, S R; Deng, X; Young, R

A method is described of forming hydrogenated amorphous germanium alloy material, said material characterized by (a) the substantial absence of germanium hydrides, other than the monohydride, (b) a mobility-lifetime product for nonequilibrium charge carriers therein of about 10 [sup [minus]8] cm[sup 2]/V, and (c) a density of defect states in the band gap of the host matrix thereof of less than about 1 x 10[sup 17]/cm[sup 3]; said method comprising the steps of: providing a deposition chamber; providing a substrate in said deposition chamber; positioning at least one target of germanium containing material adjacent said substrate; providing a laser; evacuating said deposition chamber to a sub-atmospheric pressure; introducing into said evacuated deposition chamber a background gas including a partial pressure of at least hydrogen; and depositing, by laser ablation, germanium from said target and hydrogen from said partial pressure onto said substrate; thereby forming on said substrate a layer of hydrogenated germanium alloy material having an amorphous microstructure, said material characterized by the substantial absence of incorporated germanium hydrides, other than the monohydride, a mobility-lifetime product for nonequilibrium charge carriers therein of about 10[sup [minus]8] cm[sup 2]/V, and a density of defect states in the band gap of the host matrix thereof of less than about 1 x 10[sup 17]/cm[sup 3].

• Assignee: Energy Conversion Devices, Inc., Troy, MI (United States)
• Patent Number(s): US 5231047; A
• Application Number: PPN: US 7-811159
• OSTI ID: 6319366
• Resource Relation: Patent File Date: 19 Dec 1991
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
GERMANIUM
FABRICATION
SEMICONDUCTOR MATERIALS
ABLATION
AMORPHOUS STATE
CHARGE CARRIERS
CRYSTAL DEFECTS
DEPOSITION
GERMANIUM HYDRIDES
LASERS
PHOTOVOLTAIC CELLS
SUBSTRATES
CRYSTAL STRUCTURE
DIRECT ENERGY CONVERTERS
ELEMENTS
GERMANIUM COMPOUNDS
HYDRIDES
HYDROGEN COMPOUNDS
MATERIALS
METALS
PHOTOELECTRIC CELLS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture