Making germanium, an indirect band gap semiconductor, suitable for light-emitting devices

Tóm tắt

Germanium (Ge) is a group-IV indirect band gap semiconductor but the difference between its direct and indirect band gap is only 140 meV. It has been shown that when Ge is subjected to a tensile strain and a heavy n-doping level, room-temperature photoluminescence (PL) can be greatly enhanced. Among these two factors, achieving a heavy n-doping level in Ge (i.e., electron concentrations higher than 1 × 1019 cm−3) is a challenge since the solubility of most group-V elements (P, As, Sb) in Ge is very low. We report here Ge growth on silicon substrates using molecular beam epitaxial (MBE) technique. To enhance the n-doping level in Ge, a specific n-doping process based on the decomposition of the GaP compound has been implemented. The GaP decomposition allows producing P2 molecules, which have a higher sticking coefficient than that of P4 molecules. We show that phosphorus doping at low substrate temperatures followed by flash thermal annealing are essential to get a high doping level. We have obtained an activate phosphorus concentration up to 2 × 1019 cm−3 and room-temperature PL measurements reveal an intensity enhancement up to 50 times. This result opens a new route for the realization of group-IV semiconductor optoelectronic devices.

Từ khoá

tensile strain, heavy n-doping, Ge band gap engineering, GaP decomposition, groupIV semiconductor

Tài liệu tham khảo

Sun X, Liu J F, Kimerling L C and Michel J 2009 Appl. Phys. Lett. 95 011911
Ishikawa Y and Wada K 2010 Thin Solid Films 518 S83
Liu J, Camacho-Aguilera R, Bessette J T, Sun X, Wang X, Cai Y, Kimerling L C and Michel J 2012 Thin Solid Films 520 3354 and references therein
Liu J, Sun X, Aguilera R C, Kimerling L C and Michel J 2010 Opt. Lett. 35 679 and references therein
El Kurdi M, Fishman G, Sauvage S and Boucaud P 2010 J. Appl. Phys. 107 013710
El Kurdi M, Bertin H, Martincic E, de Kersauson M, Fishman G, Sauvage S, Bosseboeuf A and Boucaud P 2010 Appl. Phys. Lett. 96 041909
Luong T K P et al 2013 J. Appl. Phys. 114 083504
Bai Y, Lee K E, Cheng C, Lee M L and Fitzgerald E A 2008 J. Appl. Phys. 104 084518
Camacho-Aguilera R, Cai Y, Bessette J T, Kimerling L C and Michel J 2012 Opt. Mater. Express 2 146211
Madelung O 1982 Physics of Group IV Elements and III–V Compounds, Landolt-Börnstein: Numerical Data and Functional Relationships in Science and Technology vol 17a (Berlin: Springer)
Shitara T and Ebert K 1994 Appl. Phys. Lett. 65 356
Lippert G, Osten H J, Krüger D, Gaworzewski P and Eberl K 1995 Appl. Phys. Lett. 66 3197
Luong T K P et al 2014 Thin Solid Films 557 70
Le Thanh V, Bouchier D and Hincelin G 2000 J. Appl. Phys. 87 3700
(www.mbe-komponenten.de)

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