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Lattice Matched Double Heterojunction Visible Injection Laser for Room Temperature Continuous Wave Operation

IP.com Disclosure Number: IPCOM000081260D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Smith, AW: AUTHOR [+2]

Abstract

Until now CW (Continuous Wave) operation at room temperature has been achieved exclusively using the Ga(1-x)Al(x)As double heterojunction (DH) system. The active layer is constrained to Ga(1-x)Al(x)As compositions well below the direct-indirect band gap crossover point. As a result, peak emission energies for CW operation have not exceeded 1.61 eV./1/

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Lattice Matched Double Heterojunction Visible Injection Laser for Room Temperature Continuous Wave Operation

Until now CW (Continuous Wave) operation at room temperature has been achieved exclusively using the Ga(1-x)Al(x)As double heterojunction (DH) system. The active layer is constrained to Ga(1-x)Al(x)As compositions well below the direct-indirect band gap crossover point. As a result, peak emission energies for CW operation have not exceeded 1.61 eV./1/

Other materials with higher energy band gap direct crossover points, such as Ga(1-y)In(y)P, are not suitable for heterostructure lasers due to the large lattice constant dependence on composition./2/ It has been shown for the GaAs(1- x)P(x) system that the required composition changes for the DH structure produce large strains at the heterojunction boundaries, giving rise to undesirable interface states negating the beneficial effects of the structure.

However, the Ga(1-y)In(y)P system with y approx. 0.5 has a direct band gap energy, B.G. approx. 1.85 eV which is well below the direct indirect band gap crossover point, and has a lattice constant within the Ga(1-x)Al(x)As system for all values of x. Furthermore, x can be chosen so that the index of refraction of Ga(1-x)Al(x)As at 1.84 eV, is less than the index of refraction of Ga(0.5)In(0.5)P. In addition, the band gap B.G.(x) of Ga(1-x)Al(x)As can be chosen so that B.G.(x) > B.G.(y) 4kT, where B.G.(y) is the band gap of Ga(0.5)In(0.5)P. Thus, both optical an...