Optische Eigenschaften von Cadmiumselenid-Einkristallen im Ultraroten

Abstract

The room temperature absorption- and reflection-spectra of CdSe single crystals containing electron concentrationsN between 5.3 · 10¹⁶ and 7 · 10¹⁹ cm⁻³ have been measured at wavelengths ranging from 0.5 μ to 12 μ. The spectral dependence of the absorption constantK is found to be K∝ λ^{2.5 ...3.6}. An interpretation of the data in terms of the theories ofVisvanathan andFan is given. The effective mass m^* of the conduction electrons in crystals containingN > 10¹⁸ cm⁻³ is calculated from the frequency of the reflection minimum. One finds: m^*=f(N). An extrapolation forN=0 yields m^*=0.08 m₀; forN=7 · 10¹⁹ cm⁻³: m^*=0.17 m₀. Values of the effective masses in ZnO- and CdO-crystals are communicated.