Band-to-Band and Band-to-Acceptor Photoluminescence Studies in InSe under Pressure

Abstract

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.

Transport measurements in InSe under high pressure and high temperature: shallow-to-deep donor transformation of Sn related donor impurities

“…Regarding the effective mass of the density of states at the B point, the value obtained for m * B (0.85m 0 ) is around 7 times the value of m * Z and does not change with pressure within the accuracy provided by our model. This value, which should be considered as a rough estimation of m * B , fairly agrees with the value deduced from photoluminescence studies (m * B = (0.75 ± 0.05)m 0 ) [38]. The present estimates of m * B are also consistent with previous band-structure calculations [8] that show that the Z minimum is sharper than the secondary minima.…”

Photoluminescence properties of boron doped InSe single crystals

“…), respectively. Similar bands have been observed in the literature for undoped InSe and InSe crystals doped with different atoms [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The intensity and resolution of the C emission band is relatively weak compared to the other bands.…”

“…A great deal of attention has been given to the photoluminescence (PL) properties of undoped and doped InSe crystals [21][22][23][24][25][26]. Various features were observed in the PL spectra of pure and doped InSe crystals depending on the growth conditions, quality of the resulting crystals and measurement conditions [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. New bands were observed in the PL spectrum of rare-earth doped InSe crystals in the 1020-1060 nm range [24].…”

“…PL spectra obtained at 77 K for n-type pure InSe crystal showed an emission band at 1.33 eV associated with the free exciton annihilation while PL spectrum of p-type Zn doped InSe crystal obtained at the same temperature showed an emission at 1.17 eV which was considered to be a transition associated with the Zn acceptor levels [30]. In a study on p-type N-doped InSe, it was shown that the PL spectra at 10 K was dominated by a band-to-acceptor peak at 1.289 eV and its phonon replica at 1.264 eV [33]. Shigetomi et al investigated the impurity levels of n-type InSe doped with Sn by PL and Hall-effect measurements [34].…”

Electron-Beam Detection of Bits Reversibly Recorded on Epitaxial InSe/GaSe/Si Phase-Change Diodes

“…Photoreflectance showed a zerocrossing and photoluminescence showed a peak near 1.2-1.25 eV, 32) similar to previously published results. 33,34) InSe film thicknesses were usually in the 50-100 nm range, while GaSe thicknesses were typically 5-10 nm.…”