Abstract

HELLISH (Hot Electron Light Emission and Lasing in Semiconductor Heterostructure) is a novel longitudinal transport device. This has been researched extensively resulting in two main types of devices; HELLISH-1 and 2.¹,² HELLISH-1 consists of a 130Å GaAs SQW situated on the n-side of an AlGaAs p-n junction within the depletion region. Light emission is from the device surface, independent of the applied electric field and therefore exhibits an XOR function with respect to the applied voltage. Recently, a VCSEL device has been realised by incorporating an upper and lower DBR to the original structure. To date this is the first demonstration of a hot electron based VCSEL at room temperature. As shown in the key of Figure 1, HELLISH-1 forms the cavity of the VCSEL. The lower DBR has 27 periods of AlGaAs layers with varying Al concentration and provides a reflectivity better than 99%. The upper DBR has 17 periods which allows an output from the top surface in the form of lasing.

© 1998 IEEE