Preparation of low resistive unintentionally doped n-type ZnSe

This paper reports on the preparation of low resistive n-type ZnSe bulk material required as substrates for homoepitaxial growth of ZnSe-based devices. ZnSe samples were annealed in molten Zn at temperatures between 600 and 950 °C for 100 h and subsequently quenched to room temperature. Temperature-dependent Hall and conductivity measurements reveal a maximum carrier concentration of n = 1 × 10cm−3. Mobilities of up to 550 cm2 V−1 s−1 at room temperature were observed. These values are higher than previously reported for Cl-doped ZnSe molecular beam epitaxy (MBE) layers. Samples heat-treated under equal conditions but belonging to crystals of different origin show differences in the achieved free carrier concentration and distinguished photoluminescence spectra. We tentatively discuss the results in terms of impurity content and quality of used ZnSe crystals.