| Autor: |
Wenisch, H., Schüll, K., Behr, T., Hommel, D., Landwehr, G., Siche, D., Rudolph, P., Hartmann, H. |
| Zdroj: |
Journal of Crystal Growth; February 1996, Vol. 159 Issue: 1-4 p26-31, 6p |
| Abstrakt: |
The properties of light emitting diodes (LEDs) based on (Cd,Zn)Se multi-quantum-wells in ZnSe grown by molecular beam epitaxy are compared for different substrate materials. ZnSe single crystals of high structural quality grown by the iodine transport, by the sublimation method in sealed ampoules and from the melt were used as substrates for ZnSe homoepitaxy in this work. Based on high resolution X-ray diffraction (XRD), transmission electron microscopy (TEM), and electro-optical measurements, it is shown that they all are superior to similar structures grown on (001) GaAs substrates with a 5 μm thick In0.04Ga0.96As buffer which is nearly lattice matched to ZnSe. Cross sectional TEM studies indicate the III–VII–VIinterface to be the origin of dislocations observed in the LED structure, while at the homoepitaxial ZnSeZnSeinterface hardly any new dislocations are generated under optimized conditions. The full width at half maximum (FWHM) in XRD (004 reflection) of a 4 μm thick multi-quantum-well diode structure was 47 arc sec which is near to the values of the substrate material. For epilayers, values as low as 21 arc sec have been observed. In reciprocal space mapping no significant broadening due to mosaicity can be found. The LED structures were tested as edge emitters in a laser like configuration under pulsed and continuous current injection at room temperature. They emit blue-green light at 490 nm with a FWHM of only 56 meV. |
| Databáze: |
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