Acceptor Densities and Acceptor Levels in Undoped GaSb Determined by Free Carrier Concentration Spectroscopy

Abstract

Without any assumptions regarding residual impurity species in an undoped semiconductor, it is experimentally demonstrated that the densities and energy levels of impurities can be precisely determined by the graphical peak analysis method based on Hall-effect measurements, referred to as free carrier concentration spectroscopy (FCCS). Using p-type undoped GaSb epilayers grown by molecular beam epitaxy (MBE), the densities and energy levels of several acceptor species are accurately determined. Five acceptor species are detected in the undoped GaSb epilayers grown by MBE, while two are also found in ptype undoped GaSb wafers. A 21-41 meV acceptor and a 75-99 meV acceptor exist both in the epilayers and in the wafer. On the other hand, a 164-181 meV acceptor is detected in epilayers grown at an Sb 4 /Ga flux beam equivalent pressure ratio of 8 or 10, while a 259 meV acceptor is found in the epilayer grown at Sb 4 /Ga = 6. In addition, a very shallow acceptor, which is completely ionized at 80 K, is found in the epilayers. The densities of the very shallow acceptor and the 21-41 meV acceptor are minimum at Sb 4 /Ga ¼ 8, which makes the hole concentration lowest in the temperature range of the measurement.

Donor and acceptor levels in impurity-doped semiconducting BaSi2 thin films for solar-cell application

“…First, BaSi 2 materials are not well explored electrically like some others semiconductor materials, for example, 3C‐SiC or GaSb or AlGaN or GaN or GaAs, respectively. In particular, Matsuura et al, systematically studied the donors and acceptors levels in both 3C‐SiC and GaSb . Furthermore, in our experiment, we used highly resistive substrates 2000–3000 Ω cm for Hall measurement using the van der Pauw method and considered the electrical characterization data as a reference from the undoped n‐type BaSi 2 , where the electron concentration was around 5 × 10 15 cm −3 at RT, given in Fig.…”

Si Substrate Suitable for Radiation-Resistant Space Solar Cells

“…As one of the analyses, free-carrier concentration spectroscopy (FCCS) has been proposed and tested. 9,11,[38][39][40][41][42][43][44] From FCCS, the donorlike defect with E C À 0:3 eV was reported in the type-converted samples, 11) which was different from the donorlike defect with E C À 0:18 eV from DLTS. [13][14][15][16][17][18][19][20][21] The result obtained from FCCS is consistent with other reports.…”

Investigation of a distribution function suitable for acceptors in SiC

“…Free carrier concentration spectroscopy ͑FCCS͒ 8,9,11,14,15,[21][22][23] is a graphical peak analysis method for determining the densities and energy levels of acceptor species in a semiconductor using p(T), even when the number of acceptor species included in the semiconductor is unknown. Using an experimental p(T), the FCCS signal is defined as 22,23 H͑T,E ref ͒ϵ…”