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Light Emitting Silicon Diode

IP.com Disclosure Number: IPCOM000049995D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Burstein, E: AUTHOR [+2]

Abstract

When diodes in semiconductors are biased to avalanche, they are a source of a large current of hot carriers. They are extremely weak and inefficient sources of light if the bandgap is indirect as in the case of silicon. The light efficiency can be increased by using the hot carriers to excite plasma modes in metal particles and thereby to couple the energy out of the system as light. This is analogous to excitation of plasmons and coupling to light nodes in tunnel junctions but should allow much stronger pumping of the plasmon modes.

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Light Emitting Silicon Diode

When diodes in semiconductors are biased to avalanche, they are a source of a large current of hot carriers. They are extremely weak and inefficient sources of light if the bandgap is indirect as in the case of silicon. The light efficiency can be increased by using the hot carriers to excite plasma modes in metal particles and thereby to couple the energy out of the system as light. This is analogous to excitation of plasmons and coupling to light nodes in tunnel junctions but should allow much stronger pumping of the plasmon modes.

The structure is a shallow p-n junction on silicon with native oxide (10-20 A) on the top of the junction. On the surface above the native oxide, discontinuous films of metal (preferably silver or aluminum) are deposited. The structure is shown in Fig. 1. When the p-n diode is reverse biased above the threshold for avalanche breakdown, hot electrons are generated and stream toward the surface. If the p-region is thin enough, they arrive at the surface hot and will penetrate into the metal particles, still hot. In cooling, they will excite the local plasmons, which then decay by light emission.

The cold electrons can tunnel back to the silicon to discharge the particles.

A variation is shown in Fig. 2. In Fig. 2, a positive gate voltage is applied between the transparent gate and the n/+/ contacts, inducing an inversion layer. Electrons are injected into the p-region by forward biasing the p-n(1) junction....