Abstract: A cold electron emitter may include a heavily a p-doped semiconductor, and dielectric layer, and a metallic layer (p-D-M structure). A modification of this structure includes a heavily n+ doped region below the p region (n+-p-D-M structure). These structures make it possible to combine high current emission with stable (durable) operation. The high current density is possible since under certain voltage drop across the dielectric layer, effective negative electron affinity is realized for the quasi-equilibrium “cold” electrons accumulated in the depletion layer in the p-region next to the dielectric layer. These electrons are generated as a result of the avalanche in the p-D-M structure or injection processes in the n+-p-D-M structure. These emitters are stable since they make use of relatively low extracting field in the vacuum region and are not affected by contamination and absorption from accelerated ions. In addition, the structures may be fabricated with current state-of-the-art technology.

Abstract: A magnetic sensor based on efficient spin injection of spin-polarized electrons from ferromagnets into semiconductors and rotation of electron spin under a magnetic field. Previous spin injection structures suffered from very low efficiency (less than 5%). A spin injection device with a semiconductor layer sandwiched between &dgr;-doped layers and ferromagnets allows for very high efficient (close to 100%) spin polarization to be achieved at room temperature, and allows for high magneto-sensitivity and very high operating speed, which in turn allows devising ultra fast and sensitive magnetic sensors.

Abstract: A magnetic sensor uses injection of spin-polarized electrons between magnetized regions via a semiconductor and spin precession of electrons that a magnetic field being measured causes in the semiconductor. The sensor can include donor n+-doped &dgr;-layers and acceptor doped transition layers at one or both interfaces between magnetized regions and the semiconductor region. The properties of the &dgr;-doped layers and the transition layers can be adjusted to improve efficiency of injection of spin-polarized electrons into the semiconductor at small voltage between about 25 and 50 mV. One geometry for the sensor has the magnetized regions that are laterally spaced apart on a major surface of a substrate with the semiconductor being either between or adjacent to the magnetic regions to form a current path for spin-polarized electrons.

Abstract: A magnetic sensor based on efficient spin injection of spin-polarized electrons from ferromagnets into semiconductors and rotation of electron spin under a magnetic field. Previous spin injection structures suffered from very low efficiency (less than 5%). A spin injection device with a semiconductor layer sandwiched between &dgr;-doped layers and ferromagnets allows for very high efficient (close to 100%) spin polarization to be achieved at room temperature, and allows for high magneto-sensitivity and very high operating speed, which in turn allows devising ultra fast and sensitive magnetic sensors.

Abstract: A cold electron emitter may include a heavily n+ doped wide band gap (WBG) substrate, a p-doped WBG region, and a low work function metallic layer (n+-p-M structure). A modification of this structure includes heavily p+ doped region between p region and M metallic layer (n+-p-p+-M structure). These structures make it possible to combine high current emission with stable (durable) operation. The high current density is possible because the p-doped (or p+ heavily doped) WBG region acts as a negative electron affinity material when in contact with low work function metals. The injection emitters with the n+-p-M and n+-p-p+-M structures are stable since the emitters make use of relatively low extracting electric field and are not affected by contamination and/or absorption from accelerated ions. In addition, the structures may be fabricated with current state-of-the-art technology.

Abstract: A cold electron emitter may include a heavily n+ doped wide band gap (WBG) substrate, a p-doped WBG region, and a low work function metallic layer (n+-p-M structure). A modification of this structure includes heavily p+ doped region between p region and M metallic layer (n+-p-p+-M structure). These structures make it possible to combine high current emission with stable (durable) operation. The high current density is possible because the p-doped (or p+ heavily doped) WBG region acts as a negative electron affinity material when in contact with low work function metals. The injection emitters with the n+-p-M and n+-p-p+-M structures are stable since the emitters make use of relatively low extracting electric field and are not affected by contamination and/or absorption from accelerated ions. In addition, the structures may be fabricated with current state-of-the-art technology.

Abstract: A cold electron emitter may include a heavily a p-doped semiconductor, and dielectric layer, and a metallic layer (p-D-M structure). A modification of this structure includes a heavily n+ doped region below the p region (n+-p-D-M structure). These structures make it possible to combine high current emission with stable (durable) operation. The high current density is possible since under certain voltage drop across the dielectric layer, effective negative electron affinity is realized for the quasi-equilibrium “cold” electrons accumulated in the depletion layer in the p-region next to the dielectric layer. These electrons are generated as a result of the avalanche in the p-D-M structure or injection processes in the n+-p-D-M structure. These emitters are stable since they make use of relatively low extracting field in the vacuum region and are not affected by contamination and absorption from accelerated ions.