Light emitting four layer semiconductor

Claim 2

A semiconductor device comprising four pnpn layers each composed of semiconductor material having a high band gap energy and means of forward biasing said four layer device, two intermediate layers thereof having a thickness approximately equal to a diffusion length of minority carriers in the semiconductor material for small values of current therethrough while at least one of the outer layers thereof having a thickness approximately equal to or greater than another diffusion length of minority carriers in the semi-conductor material for higher values of current whereby said device provides both the negative resistance and light emission wherein said semiconductor device has the pn pn layers composed of semiconductors of compounds of groups III-V.

Claim 3

A semiconductor devices as defined in claim 1 in which the pnpn layers are composed of GaAs, two intermediate layers thereof being about 1 to 40 Mu in thickness and at least one outer layer thereof being more than 50 Mu in thickness.

Claim 4

A semiconductor device comprising a semiconductor element having first and second terminals and having a voltage-current characteristic with positive and negative resistance regions and exhibiting light emission which is proportional to the element current in both positive or negative resistance regions, said semiconductor element being of four-layer pnpn construction with three pn junctions, the thickness of the two intermediate layers being approximately equal to a diffusion length of the minority carriers in the semiconductor material for small values of the element current and the thickness of the outer layers being approximately equal to or greater than another diffusion length of the minority carriers in the semiconductor material for higher values of the element current, and biasing means connected between said first and second terminals of said element for forward biasing the two outer pn junctions of said three pn junctions and for backward biasing the intermediate pn junction, said element under the biased condition emitting light mainly in said outer layer, said biasing means including a series connected signal source for providing a sufficiently high potential across said element to cause a large carrier accumulation for cancelling said backward bias at said intermediate pn junction to allow the current to flow through said intermediate pn junction.

Claim 5

A semiconductor device comprising a semiconductor element having first and second terminals and having a voltage-current characteristic with positive and negative resistance regions and exhibiting light emission which is proportional to the element current in both positive or negative resistance regions, said semiconductor element being of four-layer pnpn construction with three pn junctions, the thickness of the two intermediate layers being approximately equal to a diffusion length of the minority carriers in the semiconductor material for small values of the element current and the thickness of the outer layers being approximately equal to or greater than another diffusion length of the minority carriers in the semiconductor material for higher values of the element current, and biasing means connected between said first and second terminals of said element for forward biasing the two outer pn junctions of said three pn junctions and for backward biasing the intermediate pn junction, said element under the biased condition emitting light mainly in said outer layer, said biasing means including a series connected signal source for providing a sufficiently high potential across said element to cause a large carrier accumulation for cancelling said backward bias at said intermediate pn junction to allow the current to flow through said intermediate pn junction.