Non-destructive carrier concentration determination in InAs thin films for THz radiation generating devices using fast differential reflectance spectroscopy

Abstract

We present a fast and robust optical method of determining carrier concentrations in heavily doped layered structures. We discuss several advantages of the technique as compared to other, more commonly applied methods using as an example InAs based devices used for THz radiation generation. Our approach leads to a more accurate estimation of doping levels in the investigated structures and aids the standard Hall measurements in precise predictions of radiative efficacy in the THz region. Predicted enhancement factors reproduce THz-Time Domain Spectroscopy (TDS) experiment results within a 2 % accuracy.

Contactless Measurements of Carrier Concentrations in InGaAs Layers for Utilizing in InP-Based Quantum Cascade Lasers by Employing Optical Spectroscopy

“…This allowed us to get a useful function after exponential fitting (red line). A similar procedure has been proven to be successful when applied for the analysis of Berreman minima in the case of carrier concentration determination in InAs layers [ 23 ], using data from Hinkey et al [ 24 ]. By open squares we marked nominal concentration values on the fitted line at the respective wavenumbers.…”