PENGARUH STRAIN BIAXIAL MENGGUNAKAN METODE DENSITY FUNCTIONAL THEORY TERHADAP SIFAT TERMOELEKTRIK MATERIAL ZnO ROCK SALT

MUHAMMAD HABIBIE RAHMAN, . (2026) PENGARUH STRAIN BIAXIAL MENGGUNAKAN METODE DENSITY FUNCTIONAL THEORY TERHADAP SIFAT TERMOELEKTRIK MATERIAL ZnO ROCK SALT. Sarjana thesis, UNIVERSITAS NEGERI JAKARTA.

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Abstract

ZnO merupakan material semikonduktor oksida yang berpotensi sebagai material termoelektrik karena melimpah, non-toksik, dan stabil pada temperatur tinggi. Namun, fase wurtzite ZnO memiliki bandgap lebar (~3,37 eV) yang membatasi konsentrasi pembawa muatan pada temperatur ruang. Fase rock salt ZnO, yang terbentuk pada tekanan tinggi (~10 GPa), memiliki bandgap lebih sempit sehingga berpotensi meningkatkan performa termoelektrik, namun pengaruh strain Biaxial terhadap sifat termoelektriknya belum banyak dikaji dalam literatur. Penelitian ini bertujuan menganalisis pengaruh strain Biaxial (-6%, -3%, 0%, +3%, +6%) terhadap struktur elektronik dan sifat termoelektrik ZnO rock salt menggunakan metode Density Functional Theory (DFT) dengan pendekatan GGA+U, dikombinasikan dengan teori transport semi-klasik Boltzmann (BoltzTraP2) pada suhu 300 K. Hasil perhitungan menunjukkan bahwa bandgap menurun secara monoton dari 2,835 eV (strain -6%) menjadi 1,159 eV (strain +6%), tanpa mengubah karakter indirect bandgap maupun stabilitas struktur kristal. Regangan tarik (tensile) meningkatkan konduktivitas listrik dan power factor secara signifikan, menghasilkan figure of merit (ZT) tertinggi sebesar 0,7831 pada strain +3%, dibandingkan 0,7389 pada kondisi tanpa strain dan hanya 0,5396 pada strain -6%. Temuan ini menunjukkan bahwa strain Biaxial tensile merupakan strategi rekayasa yang efektif untuk mengoptimalkan performa termoelektrik ZnO rock salt tanpa mengubah komposisi kimia material. ***** ZnO is an oxide semiconductor material with strong potential as a thermoelectric material due to its abundance, non-toxicity, and stability at high temperatures. However, the wurtzite phase of ZnO has a wide bandgap (~3.37 eV) that limits charge carrier concentration at room temperature. The rock salt phase of ZnO, which forms under high pressure (~10 GPa), has a narrower bandgap and may therefore offer improved thermoelectric performance, yet the effect of Biaxial strain on its thermoelectric properties remains largely unexplored in the literature. This study aims to analyze the influence of Biaxial strain (-6%, -3%, 0%, +3%, +6%) on the electronic structure and thermoelectric properties of ZnO rock salt using Density Functional Theory (DFT) with the GGA+U approach, combined with semi-classical Boltzmann transport theory (BoltzTraP2) at 300 K. The results show that the bandgap decreases monotonically from 2.835 eV (-6% strain) to 1.159 eV (+6% strain), while the indirect bandgap character and crystal structure stability are preserved. Tensile strain significantly enhances electrical conductivity and power factor, yielding the highest figure of merit (ZT) of 0.7831 at +3% strain, compared to 0.7389 for the unstrained condition and only 0.5396 at -6% strain. These findings indicate that tensile Biaxial strain is an effective engineering strategy for optimizing the thermoelectric performance of ZnO rock salt without altering the material's chemical composition.

Item Type:	Thesis (Sarjana)
Additional Information:	1). Prof. Dr. Iwan Sugihartono, M.Si. ; 2). Dr. Teguh Budi Prayitno, M.Si.
Subjects:	Sains > Fisika
Divisions:	FMIPA > S1 Fisika
Depositing User:	Muhammad Habibie Rahman .
Date Deposited:	10 Aug 2026 06:48
Last Modified:	10 Aug 2026 06:48
URI:	http://repository.unj.ac.id/id/eprint/69396

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