G-Doping-Based Metal-Semiconductor Junction

Avtandil Tavkhelidze,Larissa Jangidze,Nima E Gorji,Zaza Taliashvili

doi:10.3390/coatings11080945

Avtandil Tavkhelidze, Larissa Jangidze + Show 2 more

Open Access

https://doi.org/10.3390/coatings11080945

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Journal: Coatings	Publication Date: Aug 7, 2021
Citations: 7	License type: CC BY 4.0

Affiliation: Ilia State University, Dublin City University

Abstract

Geometry-induced doping (G-doping) has been realized in semiconductors nanograting layers. G-doping-based p-p(v) junction has been fabricated and demonstrated with extremely low forward voltage and reduced reverse current. The formation mechanism of p-p(v) junction has been proposed. To obtain G-doping, the surfaces of p-type and p+-type silicon substrates were patterned with nanograting indents of depth d = 30 nm. The Ti/Ag contacts were deposited on top of G-doped layers to form metal-semiconductor junctions. The two-probe method has been used to record the I–V characteristics and the four-probe method has been deployed to exclude the contribution of metal-semiconductor interface. The collected data show a considerably lower reverse current in p-type substrates with nanograting pattern. In the case of p+-type substrate, nanograting reduced the reverse current dramatically (by 1–2 orders of magnitude). However, the forward currents are not affected in both substrates. We explained these unusual I–V characteristics with G-doping theory and p-p(v) junction formation mechanism. The decrease of reverse current is explained by the drop of carrier generation rate which resulted from reduced density of quantum states within the G-doped region. Analysis of energy-band diagrams suggested that the magnitude of reverse current reduction depends on the relationship between G-doping depth and depletion width.

Highlights

Theof red thecolor p-p(v) junction, which is connected in series. This is evident from the reverse currentcorresponds to the nanograting area recorded using two probes; the blue color refers to the voltage dependence of plain the p-p(v)
It was found that forward current-voltage dependence of p-p(v)-M and p+-p(v)-M junctions are well described by the Shockley equation
The reverse current of p-p(v)-M junction is considerably lower with respect to the p-M junction

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Nanograting (NG) patterns have been shown to dramatically change the electronic [5,6,7], magnetic [8,9], optical [10,11,12,13,14], and electron emission [15,16] properties of the semiconductor substrate when the grating depth becomes comparable with de Broglie wavelength of electrons This can be attributed to the special boundary conditions enforced by the NG on the wave function. The Fermi energy rises under the patterned region because the electron concentration, n, in the conduction band increases. We call this geometry-induced electron doping (G-doping) [5].

Basic energy-band

Sample

Results and Discussion

Shockley expression with ideality factor of 5 with 10 the

Istrongly depends on carrier

Conclusions