Determination of band gap narrowing and hole density for heavily C-doped GaAs by photoluminescence spectroscopy

Abstract

The energy band gap narrowing effect in heavily C-doped GaAs was investigated using photoluminescence spectroscopy. The band gap was determined over the hole density range 1017–4×1020 cm−3 at 10 and 300 K. The band gap data at low temperatures confirm the available theoretical calculations up to 1020 cm−3. An unexpected temperature dependence of the observed band gap at high doping levels is discussed on the basis of carrier-phonon interactions. We present an analysis of the band gap narrowing effect that can be used for nondestructive measurement of hole densities in the range 1017–4×1020 cm−3.

Low temperature photoluminescence properties of Zn-doped GaAs

“…In this figure, we have also plotted the reported results for Zn, Be, and C doped GaAs measured at temperatures between 4.2 and 77 K, as the band gap shrinkage is independent of temperature [9,20]. The measured band gap shrinkage of carrier concentration of Be, C, and Zn-doped GaAs, exhibited consistent agreement between each other [9,14,18,24,25,28,37]. Fig.…”

“…The hole concentration measured at 300 K was used in 4.2 and 120 K photoluminescence studies and the same procedure was followed by several authors [14,18,25,28]. P-type layers with thickness of about 1.2 mm were chosen for analysis to reduce thickness measurement errors.…”

“…Band gap shrinkage due to heavy doping is a well known phenomenon in III -V compound semiconductors, particularly observed in GaAs by PL spectroscopy [9,10,[20][21][22][23][24][25][26]. The luminescence properties are dependent on the growth conditions (methods), doping concentrations, impurity species, growth temperatures, etc.…”

Influence of growth parameters on the composition and impurity levels of intrinsically carbon doped AlxGa1−xAs

“…Furthermore, it was observed that x is close to x G throughout the investigated range, which is in agreement with literature [21,22]. For lower growth temperatures and V/III ratios, XRD and PL could not be used for determination of the aluminum fraction, because high carbon concentrations lead to lattice contraction and a shift in the band gap [23,24]. In this parameter range, ICP-AES as performed at our institute seemed less reliable than SIMS.…”

Photoreflectance study of GaMnAs layers grown by MBE

“…(3). Is important to comment that this equation is a semiempirical expression, which is a useful tool for determination of carrier concentration for shallow dopants [13,14]. However Mn is a deep acceptor in GaAs, therefore a comparison with carrier concentration obtained from the Hall measurements is necessary, and these values are plotted as solid circles in the inset of Fig.…”