n-Type Chalcogenides by Ion Implantation

TL;DR

This paper demonstrates the first successful n-type doping of chalcogenide glasses using ion implantation of bismuth, enabling new electronic functionalities in phase-change and optical devices.

Contribution

It introduces a novel ion implantation method for n-type doping of chalcogenide glasses, significantly reducing dopant concentrations needed compared to traditional melt-doping.

Findings

Bi ion implantation induces n-type conductivity in GeTe and GaLaSO glasses.

Rectification and photocurrent observed in Bi-implanted GaLaSO devices.

N-type doping achieved at 100 times lower Bi concentration than melt-doping methods.

Abstract

Carrier-type reversal to enable the formation of semiconductor p-n junctions is a prerequisite for many electronic applications. Chalcogenide glasses are p-type semiconductors and their applications have been limited by the extraordinary difficulty in obtaining n-type conductivity. The ability to form chalcogenide glass p-n junctions could improve the performance of phase-change memory and thermoelectric devices and allow the direct electronic control of nonlinear optical devices. Previously, carrier-type reversal has been restricted to the GeCh (Ch=S, Se, Te) family of glasses, with very high Bi or Pb doping concentrations (5 to 11 at.%) incorporated during high-temperature glass melting. Here we report the first n-type doping of chalcogenide glasses by ion implantation of Bi into GeTe and GaLaSO amorphous films, demonstrating rectification and photocurrent in a Bi-implanted GaLaSO device. The electrical doping effect of Bi is observed at a 100 times lower concentration than for Bi melt-doped GeCh glasses.