Browse Prior Art Database

Integrated Three-Terminal Led/Photodetector

IP.com Disclosure Number: IPCOM000046068D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Matino, H: AUTHOR

Abstract

This article describes an integrated three-terminal light-emitting/ photo detecting array structure which consits of a LED (light-emitting diode) region and a photodetector region. The band gap of the material of the LED region is larger than that of the photodetector region to reduce optical absorption in the LED region.

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Integrated Three-Terminal Led/Photodetector

This article describes an integrated three-terminal light-emitting/ photo detecting array structure which consits of a LED (light-emitting diode) region and a photodetector region. The band gap of the material of the LED region is larger than that of the photodetector region to reduce optical absorption in the LED region.

A typical structure is shown in Fig. 1. Typical impurity concentration and atomic profile, x, in Ga/l-x/Al/x/As is shown in Fig. 2. The LED region includes N+ region 1 and P region 2 which form the N/+/P light-emitting junction, and the photodetector region includes P region 2, N/-/ region 3 and N+ region 4 which form the PN/-/N/+/ junction. The value of x at the N/+/P junction is 0.35 for a light emission of 660 nm. The value of x at the surface is 0.45 which is larger than that of the N/+/P junction to eliminate undesired surface recombination of carriers. The carrier concentration Nc of the N/-/ region 3 is 10/16/cm/-3/, which means that the thickness of the depletion layer is 1 mm at a bias voltage of -10 V in the PN/-/N/+/ detector junction. The value of x can be reduced to zero in the depletion layer for performing effective photodetection of a longer wavelength range.

Advantage of this structure is the realization of an independent selection of the optimum doping level and the atomic profile required for both LED and detector, respectively. Another advantage of the structure is that it produces...