Photoluminescence Characterisation of High Current Density Resonant Tunnelling Diodes for Terahertz Applications

Kristof J. P. JACOBS  Benjamin J. STEVENS  Richard A. HOGG  

IEICE TRANSACTIONS on Electronics   Vol.E99-C   No.2   pp.181-188
Publication Date: 2016/02/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E99.C.181
Type of Manuscript: INVITED PAPER (Special Section on Recent Advances in Photonics Technologies and Their Applications)
resonant tunnelling diode,  high-speed electronics,  terahertz,  photoluminescence,  

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High structural perfection, wafer uniformity, and reproducibility are key parameters for high-volume, low cost manufacture of resonant tunnelling diode (RTD) terahertz (THz) devices. Low-cost, rapid, and non-destructive techniques are required for the development of such devices. In this paper, we report photoluminescence (PL) spectroscopy as a non-destructive characterisation technique for high current densityInGaAs/AlAs/InP RTD structures grown by metal-organic vapour phase epitaxy (MOVPE) for THz applications. By using a PL line scanning technique across the edge of the sample, we identify characteristic luminescence from the quantum well (QW) and the undoped/n+ InGaAs layers. By using the Moss-Burstein effect, we are able to measure the free-electron concentration of the emitter/collector and contact layers in the RTD structure. Whilst the n+ InGaAs luminescence provides information on the doping concentration, information on the alloy composition and compositional variation is extracted from the InGaAs buffer layer. The QW luminescence provides information on the average well width and provides a monitor of the structural perfection with regard to interface and alloy disorder.