Abstract:
An apparatus for forming an evaporated pnictide-containing film on a substrate characterised in that it comprises a cracker adjacent to the substrate is disclosed. A process for the production of an evaporated pnictide-containing film on a substrate characterised in that it comprises deposition thereof using a cracker is also disclosed. Referring to the accompanying illustrative drawing, the present apparatus may comprise a cracker 34 adjacent to a substrate 28. The present invention represents an advance over the prior art.
Abstract:
A semiconductor characterised in that it has a pnictide-rich layer on a surface thereof is disclosed, as is the production thereof. A new form of pnictide characterized in that it comprises a layer of amorphous pnictide-rich material having a layer-like local order. The accompanying illustration shows a comparison of Raman spectra from which it may be concluded that the local order of the present fibres is the amorphous counterpart of the puckered layer-like, sheet-like crystalline structure of black phosphorus. In general terms, pnictide thin films, particularly phosphorus, grown on III-V semiconductors, particularly InP, GaP and GaAs, are amorphous and have a novel layer-like, puckered sheet-like local order. The thin films are typically 400 Angstroms (4x 10- 6 cms) thick and grown preferably by molecular beam deposition, although other processes, such as vacuum evaporation, sputtering, chemical vapour deposition and deposition from a liquid melt, may be used. The layers may be grown on the , and surface of III-V crystals. The pnictide layer reduces the density of surface states and allows the depletion layer to be modulated, the surface barrier reduced, the electron concentration at the surface increased and there is a decrease in the surface recombination velocity and an increase in the photoluminescence intensity. The layers may be utilized in MIS and Metal-semiconductor (Schottky) devices, for example, to insulate and passivate MISFETS, to passivate MESFETS, to reduce the surface current component of the reverse bias dark current in P-I-N and avalanche diodes and to improve performance of opto-electronic devices, such as light-emitting diodes, lasers, solar cells, photo-cathodes and photo-detectors. The pnictide layer may be applied to intermetallic and compound semiconductors having a pnictide component. The pnictides may be phosphorus, arsenic, antimony or bismuth, or combinations thereof. The present invention represents an advance over the prior art.
Abstract:
A vapour deposition process characterised in that an alkali metal intercalate is used as a source of alkali metal vapour is disclosed. The use of an alkali metal intercalate as a source of alkali metal vapour in a vapour deposition process is also disclosed, as in a source of alkali metal vapour for use in a vapour deposition process comprising an alkali metal intercalate. For example, a potassium graphite intercalate, KC 8 , may be heated to give a slow controlled release of potassium vapour for subsequent reaction with phosphorus vapour. Thin films of KP 15 and other polyphosphides may be produced by two-source vapour transport and by vacuum co-evaporation utilising KC 8 as the source of potassium vapour. RbC 8 and CsC 8 may be utilized as vapour sources to form the corresponding rubidium and cesium polyphosphides. The present invention represents an advance over the prior art.
Abstract:
A semiconductor characterised in that it has a pnictide-rich layer on a surface thereof is disclosed, as is the production thereof. A new form of pnictide characterized in that it comprises a layer of amorphous pnictide-rich material having a layer-like local order. The accompanying illustration shows a comparison of Raman spectra from which it may be concluded that the local order of the present fibres is the amorphous counterpart of the puckered layer-like, sheet-like crystalline structure of black phosphorus. In general terms, pnictide thin films, particularly phosphorus, grown on III-V semiconductors, particularly InP, GaP and GaAs, are amorphous and have a novel layer-like, puckered sheet-like local order. The thin films are typically 400 Angstroms (4x 10- 6 cms) thick and grown preferably by molecular beam deposition, although other processes, such as vacuum evaporation, sputtering, chemical vapour deposition and deposition from a liquid melt, may be used. The layers may be grown on the , and surface of III-V crystals. The pnictide layer reduces the density of surface states and allows the depletion layer to be modulated, the surface barrier reduced, the electron concentration at the surface increased and there is a decrease in the surface recombination velocity and an increase in the photoluminescence intensity. The layers may be utilized in MIS and Metal-semiconductor (Schottky) devices, for example, to insulate and passivate MISFETS, to passivate MESFETS, to reduce the surface current component of the reverse bias dark current in P-I-N and avalanche diodes and to improve performance of opto-electronic devices, such as light-emitting diodes, lasers, solar cells, photo-cathodes and photo-detectors. The pnictide layer may be applied to intermetallic and compound semiconductors having a pnictide component. The pnictides may be phosphorus, arsenic, antimony or bismuth, or combinations thereof. The present invention represents an advance over the prior art.
Abstract:
A vapour deposition process characterised in that an alkali metal intercalate is used as a source of alkali metal vapour is disclosed. The use of an alkali metal intercalate as a source of alkali metal vapour in a vapour deposition process is also disclosed, as in a source of alkali metal vapour for use in a vapour deposition process comprising an alkali metal intercalate. For example, a potassium graphite intercalate, KC 8 , may be heated to give a slow controlled release of potassium vapour for subsequent reaction with phosphorus vapour. Thin films of KP 15 and other polyphosphides may be produced by two-source vapour transport and by vacuum co-evaporation utilising KC 8 as the source of potassium vapour. RbC 8 and CsC 8 may be utilized as vapour sources to form the corresponding rubidium and cesium polyphosphides. The present invention represents an advance over the prior art.
Abstract:
An apparatus for forming an evaporated pnictide-containing film on a substrate characterised in that it comprises a cracker adjacent to the substrate is disclosed. A process for the production of an evaporated pnictide-containing film on a substrate characterised in that it comprises deposition thereof using a cracker is also disclosed. Referring to the accompanying illustrative drawing, the present apparatus may comprise a cracker 34 adjacent to a substrate 28. The present invention represents an advance over the prior art.