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The ongoing pursuit for laser device emitting in the near‐infrared spectral region on GaAs substrates has led to various material systems and device concepts. Alloys containing dilute amounts of Bismuth are promising candidates due to the already substantial band gap shift when incorporating low molar fractions of Bi in the GaAs host lattice. However, devices emitting at technologically essential wavelengths of 1.3 and 1.55 μm have yet to be demonstrated using this material system. Especially the non‐equilibrium nature of the growth conditions required to grow the metastable material makes epitaxial growth with high molar fractions of Bi challenging. An alternate approach to reach the desired wavelengths exploits a type‐II band alignment between two materials to push the emission wavelength further into the telecom bands. Here, room‐temperature laser operation of the first type‐II structure employing Ga(As,Bi) as hole confining layer and (Ga,In)As as electron confining layer is demonstrated. Sample growth is conducted by low‐pressure metalorganic vapour phase epitaxy. Broad area laser devices are processed and characterized by electroluminescence measurements. A threshold current density of 3.86 kA/cm2 and emission wavelength of 1037 nm are observed, showing this device concept's potential for future lasers in the telecom bands.

Energy efficiency, superior performance, and long-term reliability are crucial advantages of GaAs-based semiconductor laser diodes featuring strained type-I quantum wells as active regions. This class of semiconductor structures provides very good performance in the near-infrared spectral range. Achieving longer wavelength emission on GaAs substrates has proven to be difficult so far. Alloys including nitrogen (N) and bismuth (Bi) promise active materials with the possibility to push this accessible emission wavelength range toward the telecommunication bands. The alloys show a drastic decrease in the band-gap energies already for small fractions of the respective elements. However, the strong nonequilibrium nature of such multinary alloys has rendered sufficient incorporation with reasonable material quality impossible so far, mandating alternate approaches. Here, we embed a Ga­(As,Bi) quantum well (QW) between two Ga­(N,As) QWs in a so-called W-type quantum well heterostructure (WQW). This approach has the potential to achieve significant optical gain due to sufficient wave-function overlap, which is enhanced compared to type-II heterostructures. In particular, we realize WQWs with emission wavelengths around 1.1, 1.3, and 1.4 μm by drastically altering the growth conditions compared to standard growth conditions established for type-I QW structures. This particularly applies to Bi segregated at the interfaces in the structure. The resulting recipes enable the future growth of tailored WQWs for even longer emission wavelengths, e.g., extending beyond the telecom bands into the fingerprint region in the midinfrared.

Tertiarybutylarsine (TBAs) and tertiarybutylphosphine (TBP) are getting more and more established as group V precursors for the growth of V/III semiconductors by metal organic vapor phase epitaxy (MOVPE). Due to this development, the thermal decomposition of these precursors was studied during the growth of GaAs and GaP utilizing the Ga precursors, trimethylgallium (TMGa), triethylgallium (TEGa), and tritertiarybutylgallium (TTBGa), in a horizontal AIXTRON AIX 200 GFR MOVPE system. The decomposition and reaction products were measured in line with a real-time Fourier transform quadrupole ion trap mass spectrometer from Carl Zeiss SMT GmbH. The decomposition temperatures and the related activation energies were determined for all the mentioned precursors under comparable reactor conditions. The decomposition curves suggest, on the one hand, a catalytic effect of the GaAs surface on the decomposition of TBAs. On the other hand, the decomposition products indicate alkyl exchange as a relevant step during the bimolecular decomposition of TBAs and TBP with the Ga precursors TMGa, TEGa, and TTBGa. The catalytic reaction reduces the decomposition temperature of TBAs and TBP by up to 200 °C. In addition, for the growth of GaAs with TBAs and TEGa and for the growth of GaP with TBP and TEGa, a significant decrease of the decomposition temperature with an increasing V/III ratio is observed. This behavior, which is related to an alkyl exchange reaction, gives insights into the low-temperature growth of GaAs and GaP and is converted into an effective V/III ratio. Finally, the growth of GaAs with TTBGa and TBAs is realized at 300 °C below the unimolecular decomposition temperature of TBAs, underlining the catalytic effect of the GaAs surface. Altering the growth surface with trimethylbismuth led to the prevention of the catalytic effect.

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