Room-temperature photoluminescence of erbium-doped hydrogenated amorphous silicon

Abstract

A comparison of the photoluminescence of Er-doped hydrogenated amorphous silicon and crystalline silicon a-Si:H(Er) and c-Si(Er), is presented. It is shown that a-Si:H(Er) exhibits efficient room-temperature photoluminescence at 1.537 μm which is as strong as the emission from optimized c-Si(Er) at 2 K. Most remarkably, there is practically no temperature quenching of the emission intensity in the range 2–300 K. The experiments suggest that the lifetime connected with the Er-induced emission is considerably shorter in a-Si:H(Er) than in c-Si(Er) which may be responsible for the different dependences of the photoluminescence intensity on the temperature, chopping frequency, and excitation power.

Effects of Si nanocluster size and carrier–Er interaction distance on the efficiency of energy transfer

“…For Er-doped c-Si, the high excitation cross-section s exc ($10 À15 cm 2 ) of Er is strongly thwarted by a strong temperature quenching of the Er photoluminescence (PL) induced by energy back-transfer and Auger processes [2][3][4]. This PL temperature quenching is much weaker for Er-doped a-Si [5], but at the expense of an emission lifetime of only tens of microseconds [6]. In contrast, Er-doped SO offers the double advantage of good thermal stability of Er PL and an emission lifetime as high as 11 ms, but suffers from a low s exc ($10 À20 cm 2 ) [7].…”

Formation of erbium–oxygen nanoclusters in erbium‐doped oxidized amorphous silicon

“…One of the widely used approaches for the solution of this problem is doping of silicon with erbium, which in an intra-ion radiative transition emits light of 1.5 µm wavelength, corresponding to minimum losses in fiber-optics transmission lines. As an alternative to erbium-doped crystalline silicon, characterized by fairly strong quenching of erbium luminescence with rise of temperature, amorphous silicon was proposed as a promising matrix with a larger bandgap [2,3].…”

1.54 μm luminescence quenching of erbium‐doped hydrogeated amorphous silicon deposited by D.C. magnetron sputtering

“…It has been suggested that the strong thermal quenching of photoluminescence in c-Si(Er) arises from the thermally induced depopulation of the Er-induced impurity donor state, which presumably is located 15-170 meV below the conduction band edge. Within this interpretation the relative weak temperature dependence in a-Si:H<Er> suggest that the Er-related level is positioned deeper in the forbidden gap in a-Si:H that in c-Si(Er) [1]. In our previous work [7] we have clearly shown that the structure of the a-Si:H film is affected when erbium is incorporated onto the host matrix.…”

“…The use of an amorphous matrix allows to surmount these problems. This is the reason why several research teams are studying the erbium doping of a-Si:H [1][2][3]. Hydrogenated amorphous silicon is a promising host material to obtain intense Er 3+ emission due to its large modulable bandgap [4].…”