QUANTUM-WELLS WITH ZINCBLENDE MNTE BARRIERS

In this paper we describe a series of MnTe/CdTe/MnTe and MnTe/InSb/MnTe single quantum well structures. For the CdTe quantum wells we report the observation of luminescence covering the entire visible range from red to blue; a quantized state in the InSb well is used to implement resonant tunneling. X-ray diffraction and transmission electron microscopy (TEM) were used to evaluate the microstructural quality of the structures. Dark-field TEM showed that, in spite of the 2.3% lattice mismatch, the MnTe layers remained pseudomorphic and dislocation-free. High resolution images (also used to determine dimensional details) indicated that the interfaces were atomically abrupt, and that the CdTe and InSb wells were essentially unstrained in each of the structures; most of the strain was contained in the MnTe barrier layers. Optical properties of the single quantum well structures have been studied using photoluminescence and photoluminescence excitation spectroscopy. Blue luminescence at 2.59 eV (n = 1 transition) has been observed from a structure with a 10 angstrom CdTe well. The negative differential resistance observed from MnTe/InSb resonant tunneling structures represents, to our knowledge, the first report of a dimensionally quantized state in InSb.