Influence of LPE growth conditions on the electroluminescence properties of InP/InGaAs(P) infrared emitting diodes

Liquid phase epitaxial growth of InP/InGaAs(P) infrared emitting diodes was studied systematically. Small area surface emitting LED chips were prepare d to cover completely the 1100-1700 nm wavelength ranges. Nine different di odes were fabricated with optimal spacing of the peak emission wavelengths in order to have sufficient over lapping of their spectra, Efficient LEDs w ith narrow spectra have been realised by careful selection of the layer str ucture and growth conditions. Thick active layers with constant composition find abrupt interfaces have been grown for each emission wavelength, The l ong wavelength diodes (1275-1675 nm) were grown with additional quaternary layer(s) to prevent the melt-back of the active layer by InP melt. Low grow th temperature (590 degreesC) was used to prepare the LED structures. III t he spectral range of 1250-1520 nm higher growth temperatures (625-645 degre esC) were necessary to improve the device parameters. Such phenomena confir m the existence of the miscibility eap in the InGaAsP quaternary crystal sy stem. Quaternary layers grown in the middle of the immiscibile region showe d non-uniform composition and ragged interfaces at the upper heterojunction . (C) 2001 Elsevier Science B.V. All rights reserved.