Texas Instruments Corporation

Raytheon Company

William R Frensley

Mark A Reed

Gary A Frazier

Burhan Bayraktaroglu

Bumman Kim

Adam J Lewis, Jr

An improved resonant tunneling device (RTD) oscillator is provided by supplying electrical power to the RTD device using a photocell and a light source such that essentially no spurious resonances are possible.

Optically powered resonant tunneling device

A tunneling device (50) with the emitter (62) to collector (58) current transported by resonant tunneling through a quantum well (52) and controlled by carriers injected into the well (52) from a base (60) is disclosed. The injected carriers occupy a first energy level in the well (52) and the resonant tunneling is thorough a second energy level in the well (52) thereby separating the controlled carriers from the controlling carriers. Another Three-terminal tunneling devices using three different bandgap semiconductor materials to segregate controlling carriers from controlled carriers are disclosed. Preferred embodiments include narrow bandgap quantum wells and medium bandgap emitters so that narrow bandgap bases may inject and withdraw controlling electrons to the well by tunneling with the controlled electron current tunneling through a higher energy level in the well or so that medium bandgap bases may control holes in the well with only a small forward bias on the emitter-base junction and thereby control electrons tunneling through the well from emitter to collector.

Three terminal tunneling device and method

A tunneling device (50) with the emitter (62) to collector (58) current transported by resonant tunneling through a quantum well (52) and controlled by carriers injected into the well (52) from a base (60) is disclosed. The injected carriers occupy a first energy level in the well (52) and the resonant tunneling is thorough a second energy level in the well (52) thereby separating the controlled carriers from the controlling carriers. Three-terminal tunneling devices using three different bandgap semiconductor materials to segregate controlling carriers from controlled carriers are disclosed. Preferred embodiments include narrow bandgap quantum wells and medium bandgap emitters so that narrow bandgap bases may inject and withdraw controlling electrons to the well by tunneling with the controlled electron current tunneling through a higher energy level in the well or so that medium bandgap bases may control holes in the well with only a small forward bias on the emitter-base junction and thereby control electrons tunneling through the well from emitter to collector.

An energy filter for carriers in semiconductor devices and devices with such filters are disclosed. The filter is a superlattice and the filtering action arises from the subbands and gaps in the conduction and valence bands of the superlattice. A heterojunction bipolar transistor with the filter between the emitter and base has carriers injected from the emitter into the base with energies confined to levels that minimize transit time across the base; a MESFET with a filter between a heterojunction source to channel has carriers injected with energies confined to minimize transit time across the channel. A diode with a filter in front of a drift region limits the spread of energies of injected carriers.

Ballistic transport filter and device

The disclosure relates to a detector of infrared radiation which employs Group III-V compound semiconductor technology and includes a conductive substrate, of a material such as GaAs. Upon this substrate is deposited a lattice structure, including thin alternating layers of a wider and a narrower energy band gap material (AlGaAs and GaAs) periodically disposed. Upon this is deposited a layer of an alloyed semiconductor of moderate bandgap, into which photoexcited carriers are injected, and upon this is deposited a layer of wider bandgap material against which the carriers are trapped and thus collected. The lattice is designed so that the energy gap between the first two bands produced by the periodic structure is equal to the infrared photon energy. The doping is such as to nearly fill the first band with free carriers. Thus infrared radiation is efficiently absorbed, generating free carriers in the second band of the lattice. The bandgap of the next layer is chosen so that these photoexcited carriers may easily pass into this layer, while those in the lower-energy band are blocked. These carriers are propelled across this next layer by an applied electric field and are collected at the interface with a wide-gap layer.

Infrared detector system based upon group III-V epitaxial material

A light modulator and a high speed spatial light modulator (230) with each pixel (231) made of stacked quarter wavelength layers (232, 234) of heterogeneous material. Each layer (232, 234) is composed of periodic quantum well structures whose optical constants can be strongly perturbed by bias on control electrodes (240, 242). The control electrodes (240, 242) act to either remove light absorbing electrons from the layer or to inject them into each layer. The effect is to produce either a highly relecting mirror or a highly absorbing structure. The spatial light modulator (230) is compatible with semiconductor processing technology. Also, a modulator invoking the Burstein effect in the form of a stack of p-n diodes is disclosed.

Spatial light modulator

A two-port monolithic microwave amplifier, which uses a distributed negative resistance diode with gain (such as an IMPATT diode) as an active element. The diode is tapered (increasing in width but not in thickness) so that, as the RF signal propagates along the diode, it sees a wider and wider active diode region. This diode is operated in the power-saturated region, so that, as the RF signal propagates along the diode, terminal voltage remains essentially constant, but the RF current increases. This configuration is inherently undirectional.

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Richardson, TX, United States of America

William R Frensley