Thin-film indium selenide prepared by reaction of selenium vapor with indium oxide

Abstract

N,N-dimethylethylenediamine were used instead. Orange yellowish needles (0.15 g, 75%) resulted after etheral workup. 2((CHz)2N+(Me)3). The procedure for preparing 2(Py+Me) was followed except that 20.9 mg (0.078 mmol) of ((CH,),N(CH,),) and 67 ML (0.78 mmol) of dimethyl sulfate were used. A pale white precipitate (52 mg, 80%) wm collected. IR (Kl3r) 3080,cm-'. 'H NMR (D20) 8.73 (4 H, s), 4.64 (4 H, t, J = 7.7), 3.67 (10 H, m), 3.29 ppm (18 H, br 9). FAB MS (MNBA matrix) calculated for CXH30N4O4 438.2260, observed (M+) 438.2257. HPLC retention time 3.53 min; flow rate 0.5 mL/min. 2((CH2),N(CH3),). The procedure for 2(Py) was used except that 0.101 g (0.38 mmol) of anhydride and 142 p L (1.13 mmol) of N,N-dimethylpropylenediamine were used instead. A bright yellowish powder (0.09 g, 54%) was isolated after workup.2((CH2)3N+(Me)3). The procedure for preparing 2(Py+CH3) was followed except that 48.7 mg (0.1 mmol) of 2(CH2)3-N(CH3)2 and 106 pL (1.1 m o l ) of dimethyl sulfate were used. A pale white precipitate (48 mg, 70%) was collected. cm-' . ' H NMR (D20) 8.63 (4 H, s), 4.23 (4 H, t, J = 7.71, 3.68 (6 H, m), 3.51 (4 H, t, J = 7.7), 3.12 (18 H, br s), 2.26 (4 H, m). FAB MS (MNBA matrix) calculated for C26H34N404 466.2572, observed (M+) 466.2591. HPLC retention time 3.58 min; flow rate 0.5 mL/min.A new process involving two steps has been developed to prepare thin-film InzSe3. The first step is formation of indium oxide by spray pyrolysis of an aqueous solution of indium nitrate, and the second is reaction of this oxide with selenium vapor in nitrogen at atmospheric pressure to form InzSea. Shorter exposure time was needed for complete conversion as the temperature was increased from 400 to 500 "C. Auger depth profiling of the composition of a partially converted film indicated that the conversion process appears to involve three steps: (a) reaction between selenium vapor and the oxide at the surface; (b) subsequent diffusion of selenium into the film until much of the oxide was converted to InSe; (c) further reaction involving selenium vapor and InSe to form InzSe3. It was possible to convert InzSe3 into InSe by reacting it with indium vapor, and it was also possible to incorporate cadmium. p-type InzSe3 and n-type InSe were prepared by this relatively inexpensive process. Resistance and Hall effect measurements gave a variety of resistivity and carrier density values, depending on the preparation conditions. X-ray diffraction indicated that the InzSe3 film may consist of several crystalline phases, and optical absorption spectra indicated a direct bandgap of 1.84 eV. A direct bandgap of 3.64 eV was found for In203, which was n-type and had a very low resistivity and high electron density. IntroductionThere has been a recent interest in the growth of thin

Metal−Organic Chemical Vapor Deposition of Indium Selenide Thin Films

“…There have been a number of methods reported for the growth of indium selenide thin films, of which vacuum evaporation has been studied in the greatest detail . Other methods include: flash evaporation, MBE, reaction of selenium with InP, or In 2 O 3 , surfaces, electrochemical synthesis, solid-state pyrolysis of chemical precursors, and metal organic chemical vapor deposition (MOCVD)., − Potentially, MOCVD is the most advantageous method for film growth of the indium selenides for semiconductor device applications. However, while In 2 Se 3 has been successfully grown by MOCVD using In(SeR) 3 [R = Ph, C(SiMe 3 ) 3 24 ] and In[Se 2 CNMe( n -hexyl)] 3 25 as single-source precursors, the growth of phase-pure InSe has not been observed despite the use of a single-source precursor containing an In:Se ratio of 1:1, i.e., [Me 2 In(μ-SePh)] 2…”