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HL: Halbleiterphysik

HL 9: Heterostrukturen

HL 9.1: Vortrag

Montag, 23. März 1998, 16:00–16:15, H17

In(As,SB) superlattice and single quantum well room temperature LEDs for the near infrared region — •J. Heber¹, H. Hardaway¹, P. Moeck², C. Phillips¹, M. Pullin¹, P. Tang¹, and W.T. Yuen¹ — ¹Solid State Group, Physics Department, Imperial College, London SW7 2BZ, UK — ²Interdisciplinary Research Centre for Semiconductor Materials, Imperial College, London SW7 2AZ, UK

The 3−10µ m wavelength region is of particular interest for detecting atmospheric pollutants such as CO₂, SO₂ and NO₂. Light emitting diodes (LEDs) based on InAs/InAs_1−xSb_x heterojunctions offer the possibility of convenient room temperature sources for use in these detection systems. Temperature dependent electroluminescence (EL) spectra of MBE grown strained layer superlattices (x=12.5%) and single quantum well samples (x=16.3% and 26%) were acquired. At 20K, the quantum wells emit at 5.3µ m (x=16.3%) and 8.0µ m (x=26%), the superlattice at 4.25m. These values are in excellent agreement with the predicted values obtained from numerical calculations that include the effects of strain and non-parabolicity, and assume a type IIa band offset. At 300K, for pulsed currents of 1A the peak power outputs are 47µ W and 24µ W for the 16% and 26% single quantum wells respectively and 67µ W for the superlattice. The superlattice incorporates a pseudomorphic AlSb electron containing barrier for improved radiative efficiency.