p-Type doping of II-VI heterostructures from surface states: application to ferromagnetic Cd$_{1-x}$Mn$_x$Te quantum wells

TL;DR

This paper demonstrates an effective surface state p-type doping method for CdTe and CdMnTe quantum wells, achieving high hole densities and enabling ferromagnetism, comparable to traditional nitrogen doping.

Contribution

It introduces a surface state doping technique for II-VI quantum wells that matches the efficiency of nitrogen modulation doping and induces ferromagnetism.

Findings

Surface doping achieves hole densities >2x10^{11} cm^{-2}.

Surface doping induces carrier-mediated ferromagnetism.

Temperature dependence of photoluminescence matches nitrogen-doped quantum wells.

Abstract

We present a study of p-type doping of CdTe and Cd$_{1-x}$Mn$_x$Te quantum wells from surface states. We show that this method is as efficient as usual modulation doping with nitrogen acceptors, and leads to hole densities exceeding $2 \times 10^{11}$ cm$^{-2}$. Surface doping was successfully applied to obtain carrier-induced ferromagnetism in a Cd$_{1-x}$Mn$_x$Te quantum well. The observed temperature dependence of photoluminescence spectra, and the critical temperature, correspond well to those previously reported for ferromagnetic quantum wells doped with nitrogen.