METHOD FOR INCREASING THE BAND GAP IN PHOTORESPONSIVE AMORPHOUS ALLOYS AND DEVICES

摘要

The production of improved photoresponsive amorphous alloys (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) and devices (142, 168, 178, 192, 198, 212), such as photovoltaic, photoreceptive devices and the like; having improved wavelength threshold characteristics is made possible by adding one or more band yap increasing elements to the alloys (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) and devices (142, 168, 178, 192, 198, 212). The increasing element or elements are added at least to a portion of the active photoresponsive regions (150, 170, 172, 180, 186, 194, 208, 216) of amorphous devices (142, 168, 178, 192, 198, 212) containing silicon and fluorine, and preferably hydrogen. One adjusting element is carbon which increases the band gap from that of the materials without the adjusting element incorporated therein. Other increasing elements can be used such as nitrogen. The silicon and increasing elements are concurrently combined and deposited as amorphous alloys (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) by vapor deposition, sputtering or glow discharge decomposition. The addition of fluorine bonding and electronegativity to the alloy (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) acts as a compensating or altering element to reduce the density of states in the energy gap thereof. The fluorine bond strength allows the band gap increasing element(s) to be added to the alloy (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) to adjust the band gap without reducing the electronic qualities of the alloy (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220). Hydrogen also acts as a compensating or altering element to complement fluorine when utilized therewith. The compensating or altering element(s) can be added during deposition of the alloy (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208) 210, 214, 216, 218, 220) or following deposition. The addition of the increasing element(s) to the alloys (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) increases the band gap to a widened utilization width for a particular device (142, 168, 178, 192, 198, 212) to increase the photoabsorption efficiency and to thus enhance the device's photoresponseness without adding states in the gap which decrease the efficiency of the devices (142, 168, 178, 192, 198, 212). The band gap increasing element(s) can be added in varying amounts, in discrete layers or in substantially constant amounts in the alloys (118, 146, 148, 150, 168, 170, 172, 174, 176, 180, 194, 206, 208, 210, 214, 216, 218, 220) and devices (142, 168, 178, 192, 198, 212).