| 摘要 |
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 (4 x 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 <100>, <110> and <111> 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 phosphorous, arsenic, antimony or bismuth, or combinations thereof. The present invention represents an advance over the prior art. |
