Esaki tunnel diode

Central to electronics is the I-V measurement, that is, the measurement of the electrical current I through a device, as a function of the electrical potential, bias, or voltage V placed across it. Electrical devices can be (i) two-terminal devices (resistors, capacitors, inductors, rectifiers and vacuum-fube diodes, NDR devices), (ii) three-terminal devices (vacuum-tube triodes, bipolar junction transistors, or FETs), or, more rarely, (iii) four- or five-terminal devices (vacuum tetrodes, vacuum pentodes). Amplification is possible with two-terminal Esaki tunnel diodes and other NDR devices ( diode logic ), but most amplifying devices use fhree terminals. 

A mixed ion conductor, BaSnO, has also been tested as a contact layer on a Schottky sensor [90]. The BaSnOj/SiC sensor showed a response to oxygen and this was most pronounced at 400°C. The sensor was tested from 200°C to 700°C. Operated at 700°C, the sensor showed a negative resistance peak at a bias of 2V (Figure 2.8). This peak was accounted for by the tunneling or Esaki effect [91]. Up to an operation temperature of 400°C, thermionic emission was proposed to explain its behavior. At higher temperatures, a resistance connected in series with a Schottky diode can model the device [5, 73]. At temperatures of 500-600°C, the BaSn03 shows a mixed behavior of electronic and ion conduction, and the Nernst potential [92] can be added to the model. The complete proposed model is given in (2.9). 

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