Transition of Carrier Transport Behaviors with Temperature in Phosphorus-Doped Si Nanocrystals/SiO2 Multilayers.

Mingqing Qian,Wei Li,Jun Xu,Yang Ji,Dan Shan,Kunji Chen,Dongke Li

doi:10.1186/s11671-016-1561-z

Abstract

High-conductive phosphorus-doped Si nanocrystals/SiO2(nc-Si/SiO2) multilayers are obtained, and the formation of Si nanocrystals with the average crystal size of 6 nm is confirmed by high-resolution transmission electron microscopy and Raman spectra. The temperature-dependent carrier transport behaviors of the nc-Si/SiO2 films are systematically studied by which we find the shift of Fermi level on account of the changing P doping concentration. By controlling the P doping concentration in the films, the room temperature conductivity can be enhanced by seven orders of magnitude than the un-doped sample, reaching values up to 110 S/cm for heavily doped sample. The changes from Mott variable-range hopping process to thermally activation conduction process with the temperature are identified and discussed.

Highlights

Nanocrystalline Si materials have been extensively studied because of their novel properties and their potential applications in future electronic and optoelectronic devices [1, 2]
We found that the conductivity data of the doped Nanocrystalline Si (nc-Si)/SiO2 multilayers obtained below the room temperature (300 K) cannot be well described by the Arrhenius relationship which suggests different mechanisms dominating the carrier transport processes
In summary, un-doped and P-doped nc-Si/SiO2 multilayers are formed by 1000 °C thermal annealing the corresponding hydrogenated amorphous Si/SiO2 stacked structures

Summary

Introduction

Nanocrystalline Si (nc-Si) materials have been extensively studied because of their novel properties and their potential applications in future electronic and optoelectronic devices [1, 2]. It has been reported that nc-Si-based materials can be potentially used in light-emitting devices as well as generation solar cells [4,5,6]. Most of the published work focused on the un-doped nc-Si materials. In order to further improve the devices performance, it is necessary to study the doping effect in nc-Si materials, since it can effectively control the electronic structures and properties of semiconductors [7, 8]. It was reported that the doping of P and B in nc-Si is difficult due to Self-Purification effect, which is quite different from their bulk counterpart [8,9,10].

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Results

Conclusion