Reduction of the energy gap pressure coefficient of GaN due to the constraining presence of the sapphire substrate

Autor:	Nathan W. Cheung, Piotr Perlin, Noad A. Shapiro, Timothy D. Sands, William S. Wong, Laila Mattos, Eicke R. Weber, Joachim Krüger
Rok vydání:	1999
Předmět:	Bulk modulus Photoluminescence Materials science business.industry Band gap Wide-bandgap semiconductor Sapphire General Physics and Astronomy Optoelectronics Substrate (electronics) Thin film business Pressure coefficient
Zdroj:	Journal of Applied Physics. 85:2385-2389
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.369554
Popis:	We have performed a detailed investigation of the photoluminescence pressure dependence of heteroepitaxial GaN thin films on sapphire substrates. A comparison between as grown GaN on sapphire and free-standing GaN membranes, created using a laser assisted substrate liftoff process, revealed that the presence of the sapphire substrate leads to an energy gap pressure coefficient reduction of approximately 5%. This result agrees with the numerical simulations presented in this article. We established that the linear pressure coefficient of free-standing GaN is 41.4±0.2 meV/GPa, and that the deformation potential of the energy gap is −9.36±0.04 eV. Our results also suggest a new, lower value of the pressure derivative for the bulk modulus of GaN (B′=3.5).
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::7d9abe9735cc184a93254f71566e0e98 https://doi.org/10.1063/1.369554 Zobrazit plný text záznamu