We report on photoluminescence (PL) measurements under pressure on p-type N-doped InSe at 10 K and on n-type Si-doped InSe at room temperature. Low-temperature PL of N-doped InSe is dominated by a band-to-acceptor peak. From the pressure dependence of the ionization energy of the N related shallow acceptor, the pressure change of the hole effective mass is estimated through the Gerlach-Pollmann model for hydrogenic levels in uniaxial crystals and discussed in the framework of a k Á p model. Room temperature PL in Si-doped InSe is dominated by a band-to-band peak exhibiting a pressure shift in agreement with previous works. This PL peak has been measured up to 7 GPa and a steep reversible decrease of its intensity has been observed above 4 GPa. This decrease has been interpreted as a supplementary evidence of a direct-to-indirect gap crossover, already observed in other layered semiconductors.
We have performed photoluminescence (PL) investigations of pseudomorphic Si1–yCy/Si (y = 0.45, 1.05, and 1.62%) multiple quantum well (MQW) structures under hydrostatic pressure (0 to 8 GPa) and at low temperatures (10 to 70 K). The main MQW‐related emission, at energies below the Si band gap, consists of bound and free exciton no‐phonon lines and related Si transverse‐optic phonon replicas. All MQW‐related PL peaks shift to lower energy with increasing pressure at a rate characteristic for Γ–X indirect transitions in tetrahedral semiconductors. The total band offset and the activation energies for decay of the free and bound exciton emission increase slightly with pressure as a result of the larger negative band gap pressure coefficient of the strained pseudomorphic Si1–yCy layers compared to pure silicon. A separation of biaxial strain effects on the conduction and valence band near‐gap states in the pseudomorphic Si1–yCy layers (y ≤ 0.02) on Si indicates a decrease of the intrinsic Si1–yCy band gap which corresponds to that of pure silicon compressed to the lattice constant of the alloy. From this a type‐I band alignment with electrons and light holes localized in the SiC layers is inferred. This assignment is consistent with the dependence of PL‐peak intensities and energies on excitation power, temperature and pressure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.