Photoluminescence studies on the layer semiconductor InSe

Abstract

Laser excited photoluminescence of InSe single crystal shows three peaks at 1.311, 1.272, and 1.227 eV. The relative intensity of these peaks variation from point to point on the surface of the crystal. The high-energy peak is assigned to impurity to band transitions, the 1.277 eV to donor-acceptor type transition and 1.227 eV to transition within an impurity vacancy complex. From these peak positions and the known band gap, the donor and acceptor levels associated with these centers are estimated to be approximately 41 and 40 meV, respectively.

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.…”

“…The last term of above equation is neglected in cases where well-resolved sharp peaks are not observed in the PL spectra [23,26,46] which is also valid for our InSe crystals. Hence, we also neglected the last term in the above equation.…”

“…5a-c. According to the band structure of InSe, the energy position of this emission band corresponds to impurity-band transitions [23,26,43]. It is seen that the energy position of this band increase slightly with increasing boron concentration.…”

“…The C emission band has been attributed to donor-acceptor transitions in previous studies [23,26,42]. Energy positions of the C emission band for undoped, 0.1% and 0.5% boron doped InSe single crystals are 1.283 eV, 1.284 eV, 1.284 eV which are 69 meV, 66 meV and 61 meV below the band gap energies at 12 K, respectively.…”

“…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].…”