ABSTRACT
We report a new approach for forming electrical contacts to quantum devices with very small lateral dimensions. It utilizes epitaxially grown contacting layers on substrates patterned with a double-step mesa structure. By using appropriate step heights, the active region of the device will be located on the middle ledge, with one contact made on top of the mesa and the other contact formed on a layer grown adjacent to the bottom of the mesa. Our concept is demonstrated by forming a functional resonant interband tunneling diode on a 2-μm wide ledge. The growth and characterization of such devices are described.
