PbS<inf>(1−x)</inf>Se<inf>x</inf> single and double heterostructure diode lasers

Abstract

PbS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(1-x)</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> single heterostructure (SH) and double heterostructure (DH) diode lasers have been fabricated using a 300°C Vacuum deposition process. Epitaxial layers of p,n PbS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(1-x)</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> (x=0, 0.28, 0.54, 0.60) have been grown on bulk single crystal substrates of p,n PbS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.78</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.22</sub> in a planar configuration. At 12°K pulsed laser emission is observed at 4.98μm (SH, x=0.28), 5.60μm (DH, x=0.54) and 6.10μm (DH, x=0.60) corresponding to the bandgap energies of the grown layers. Pulsed threshold current densities at 12°K are 200 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (SH, x=0.28), 80 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (DH, x=0.54) and 60 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (DH, x=0.60). Pulsed power outputs in all modes range from 1-5 mW at 12°K with 5000 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> drive. DH lasers operate CW at 12°K. Improved DH device structures operate pulsed at 77°K with threshold current densities of 1500 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Lattice mismatches of 0.25%-1.2% do not seriously limit laser performance.