Green light emitting diodes with CdSe quantum dots

Green light emitting diodes were fabricated by molecular beam epitaxy using CdSe quantum dots (QDs) as emission layers. The diode structure was “Au electrode/p-ZnTe/pseudo-graded bandgap structure of ZnSeTe/p-ZnSe:N/undoped ZnSe/emission layer/undoped ZnSe/n-ZnSe:Cl/n-GaAs(0 0 1) substrate/In electrode”. The emission layers consisted of the CdSe QDs layers and the ZnSe intermediate layers, and were fabricated changing such structures. Green injection electroluminescence (EL) was clearly observed at room temperature at a current of 20 mA. The emission intensities were studied on the different emission layer structures. The penetration depth of carriers into the emission layer is estimated to be in the range between 60 and 120 nm in the present samples.