CHARACTERIZATION OF THE LPE GROWN INGAASP INP HETEROSTRUCTURES - IR-LED AT 1.66-MU-M USED FOR THE REMOTE MONITORING OF METHANE GAS/

Combined TEM, HREM, ED, SIMS, X-ray and electroluminescence studies we re used to characterise in detail a highly effective IR-LED emitting a t the wavelength 1.66 mu m and based on buried heterostructure 26P0.74 /In0.72Ga0.28As0.62P0.38/In0.53Ga0.47As/InP grown by liquid-phase epit axy. The InGaAsP epilayers were found to be well lattice-matched, disl ocation free and of good structural quality. A tentative explanation i s presented for the spinodal decomposition observed in InGaAsP alloys. A new type of selective methane gas sensor has been developed and fab ricated on the basis of the IR-light emitting diode mentioned above. I t is shown that the proposed type of sensor can be used for the quanti tative remote control of methane gas concentration (0.2-100%) via a fi bre glass line up to the distance of 2 x 1 km.