Temperature dependence of the energy bandgap of multi-layer hexagonal boron nitride
- Texas Tech Univ., Lubbock, TX (United States)
The temperature dependence of the energy bandgap of hexagonal boron nitride (h-BN) has been probed via photoluminescence emission characteristics of a donor-to-acceptor pair transition in a 20-layer h-BN epilayer. The results indicate that the universal behavior of bandgap decreasing with temperature is absent in multi-layer h-BN. Below 100 K, the bandgap energy variation with temperature, Eg vs. T, is dominated by the electron-phonon coupling and conforms to the common behavior of redshift with an increase in temperature. At T > 100 K, the bandgap shows an unusual blueshift with temperature, which can be attributed to the unique behavior of the in-plane thermal expansion coefficient of h-BN that becomes negative above around 60 K. Although both graphite and h-BN have negative thermal expansion coefficients in a broad temperature range, graphite has a zero energy bandgap, which makes h-BN a unique semiconductor to exhibit this unusual temperature dependence of the energy bandgap.
- Research Organization:
- Texas Tech Univ., Lubbock, TX (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- NA0002927
- OSTI ID:
- 1535328
- Alternate ID(s):
- OSTI ID: 1395378
- Journal Information:
- Applied Physics Letters, Vol. 111, Issue 13; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Electroluminescence from h-BN by using Al 2 O 3 /h-BN multiple heterostructure
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