Projects per year
Abstract
Desirable intrinsic properties, namely, narrow bandgap and high carrier mobility, make germanium (Ge) an excellent candidate for various applications, such as radiation detectors, multi-junction solar cells, and field effect transistors. Nevertheless, efficient surface passivation of Ge has been an everlasting challenge. In this work, we tackle this problem by applying thermal atomic layer deposited (ALD) aluminum oxide (Al2O3), with special focus on the process steps carried out prior to and after dielectric film deposition. Our results show that instead of conventional hydrofluoric acid (HF) dip, hydrochloric acid (HCI) pre-treatment is an essential process step needed to reach surface recombination velocities (SRVs) below 10 cm/s. The main reason for efficient surface passivation is found to be a high dielectric charge that promotes the so-called field-effect passivation. Furthermore, the results demonstrate that the post-deposition anneal temperature, time, and ambient play a role in passivating Ge-dangling bonds, but surprisingly, good surface passivation (SRV below 26 cm/s) is obtained even without any post-deposition annealing. The results pave the way for high-performance n-type Ge optoelectronic devices that could use induced junctions via negatively charged Al2O3 layers.
Original language | English |
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Article number | 111113 |
Number of pages | 7 |
Journal | APL Materials |
Volume | 9 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1 Nov 2021 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Ge
- inversion
- minority carrier lifetime
- chemical pre-treatment
- field-effect
- surface passivation
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Dive into the research topics of 'Achieving surface recombination velocity below 10 cm/s in n-type Germanium using ALD Al2O3'. Together they form a unique fingerprint.Projects
- 6 Finished
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Superior infrared sensors
Savin, H. (Principal investigator) & Pasanen, T. (Project Member)
29/01/2021 → 28/01/2023
Project: Domestic funds and foundations
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NIR: Super-sensitive ?/X- and NIR-radiation detectors via defect-free nanostructures: Next Imaging Revolution?
Vähänissi, V. (Principal investigator), Savin, H. (Project Member), Ayedh, H. (Project Member), Setälä, O. (Project Member), Radfar, B. (Project Member), Liu, H. (Project Member), Terletskaia, M. (Project Member), Lahtiluoma, L. (Project Member), Räisänen, S. (Project Member), Leiviskä, O. (Project Member) & Gosalvez, S. (Project Member)
01/09/2020 → 31/08/2024
Project: Academy of Finland: Other research funding
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HydroGer: Superior IR imaging via hydrogenated germanium nanostructures
Savin, H. (Principal investigator), Fung, J. (Project Member), Chen, K. (Project Member), Setälä, O. (Project Member) & Liu, H. (Project Member)
01/01/2020 → 31/12/2022
Project: Academy of Finland: Other research funding